1
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Hi, everyone.

2
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So today we are going to solve this question, valid palindrome, too, so this question is present

3
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only told.

4
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OK, so let's see.

5
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So this is the question really boils down to now we can read the statement here.

6
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So the input will be a string as and we have to delete at most.

7
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One character we can add makes delete one character and then we have to tell whether we can make palindrome

8
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or not.

9
00:00:29,930 --> 00:00:35,060
OK, so basically so the input will basically be a string.

10
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OK, and the output will be a boolean value, true or false?

11
00:00:41,200 --> 00:00:47,440
And our question is basically from the string, we can delete zero characters, basically do not modify

12
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the string or we can delete one character.

13
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And then we have to tell whether the leading one character can result, can make the string into a palindrome

14
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or not.

15
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OK, so you can see the example here.

16
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So in this case, ABC.

17
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OK, so ABC now, this is already a palindrome.

18
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OK, so we are not deleting any character.

19
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So basically we are deleting zero characters and the output is true.

20
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OK, so this is a palindrome.

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Now see this example, ABC.

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OK, so we have ABC now.

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Obviously this is not a palindrome, but if it will delete the character, see if we will to see, then

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it will become ABC.

25
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And this is a palindrome.

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So basically we are deleting one character and we are getting a palindrome.

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So in this case, I will return.

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True.

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OK.

30
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So at Max you can see here at Max we can delete zero one characters.

31
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OK, so at most we have to delete one character.

32
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OK, so in this case, we are not building any character, and in this case we are deleting one character

33
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to obtain the palindrome so the output will be a draw.

34
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OK, now there can be many examples like, for example, ABC.

35
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OK, so if you will delete zero characters, obviously this is not a palindrome.

36
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If you will delete one character.

37
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So let's suppose you can delete it then.

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Also, it is not a palindrome.

39
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If you will see then also it is not a palindrome.

40
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You delete be then also it is not a palindrome.

41
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So basically the output for ABC listing will be false because deleting zero or one character does not

42
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result in a palindrome.

43
00:02:24,660 --> 00:02:27,050
OK, now let's take some one example.

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For example, I have this string Abebe.

45
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OK, so this is my input now.

46
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I can delete correctly, so it will become a baby, so is it a palindrome?

47
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No.

48
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So here I deleted one character.

49
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Now we can also delete this character, for example.

50
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So it will become a verb then.

51
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Also, it is not a palindrome.

52
00:02:51,160 --> 00:02:55,080
If so, basically they can be like many cases of deleting one character.

53
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But finally, all these are not palindrome.

54
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So in this case, our output will be false.

55
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OK, so for input, Abebe, our output will be false because deleting one character cannot make the

56
00:03:08,260 --> 00:03:09,690
string into a palindrome.

57
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OK.

58
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Now let us consider this example, Abebe.

59
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OK, now if I delete, if I'm deleting led to this character.

60
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So it will become baby.

61
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Now this is a palindrome.

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So the output for the string ab is true.

63
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OK, because we can delete one character to get a palindrome.

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In this case you can also delete characters like this one.

65
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OK, then it will become a B.A. and this is also a palindrome.

66
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OK, let's take one more example.

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So let's say you have the string A, B, B, C, D, and B, OK, so in this case, if I had believed

68
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this character C.

69
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Then what will happen, so it will become A, B, the the B, so basically it will become a palindrome.

70
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OK, so the output for this string will be through.

71
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OK, now let's come to the question.

72
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So how are we going to solve this problem?

73
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OK, so how to solve this problem?

74
00:04:21,290 --> 00:04:23,750
So basically, this is a very simple problem.

75
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It is just a modification of the like checking palindrome problem.

76
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OK, so it is just the modification of a palindrome problem.

77
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Now let's see how we can solve this problem.

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So basically, let's take an example.

79
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So what we will do.

80
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OK, so let's take an example, let's take a small example first so I have this string ABC and let's

81
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say we have B and E, so this is already a palindrome.

82
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OK, so I will keep two pointer start pointer and pointer.

83
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OK, so start and they the article.

84
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So move ahead, start will come here and will come here.

85
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So startlingly equal.

86
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Movahed So this is start and this is and start and end.

87
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They both are equal so move ahead then finally start will become good and end and we can say this is

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already a palindrome.

89
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OK, so this is already a palindrome.

90
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So we will return.

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True.

92
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Now let's see a case where I have to delete one character to obtain the palindrome.

93
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So suppose I have this problem.

94
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A baby.

95
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OK, so this is my starting point, this is my end point.

96
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Now, starting, they are not equal.

97
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OK, so A and B, they are not equal.

98
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So I have two cases, rather two cases.

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Either I can delete A or I can be OK.

100
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I can delete only one character.

101
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OK, so either I can delete it or I can delete B academics.

102
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I can delete only one character so I can delete more than one characters.

103
00:06:04,540 --> 00:06:07,070
So let's suppose I am deleting it.

104
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Then the string will become baby.

105
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And if I were delete B then it will become a B.

106
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OK, now I will check this string for the palindrome.

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So this thing is palindrome.

108
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So basically the output will be true.

109
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So this jingled also coming out of a palindrome.

110
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So the output is true.

111
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OK, so in this case for the string ab what I will do, my output will be a true.

112
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OK, now suppose the string was, let's say a, B, A and let's say the OK, so in this case again.

113
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So this is my start pointer.

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This is my end pointer.

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So start and they are not equal.

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So I have two cases.

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Either I can delete it or I can delete the.

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So if I am deleting a I am deleting it then it will become B ID or I can delete these.

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So I am deleting the then the string will become a, b, a..

120
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OK, so this is not a palindrome, so it is false and this string is a palindrome.

121
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That output is true.

122
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OK, so if I will delete the character D then the string will become palindrome.

123
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So what I will do.

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So my output will be true basically.

125
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OK, so I will return true for the string early.

126
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OK, so for the string ability, if I read the character D then the output is basically a palindrome.

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OK, so our approach will be very simple.

128
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So what.

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So what we are going to do here is.

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So suppose we have a very long string, let's say a B and finally, let's little Dabi and then we have

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some characters and then again, we have, let's say, a day and let's see, OK, and these are.

132
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So this is a very big string.

133
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OK, so what will be our approach?

134
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So our approach is going to be very simple.

135
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I will keep 2.0.

136
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So this is a start point.

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This is an appointed.

138
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So start and end the article.

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So move ahead.

140
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Start will come here and we'll come here, start and end the article to move ahead.

141
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So this is my start and this is my end.

142
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OK, so now here the start and end.

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They are different.

144
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OK, so B and C, they are different.

145
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So whenever we will encounter this case, what will happen?

146
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We have two situations.

147
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We have two cases I can relate B or I can see.

148
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So if I am deleting B, if I delete B, then I am writing from here, then my string will be this one.

149
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OK, so.

150
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I have to check this string, so if this string is a palindrome, then I will return to.

151
00:09:01,110 --> 00:09:06,990
Now, the next case can be, I am deleting the correct policy, so if I were the correct WTC, then

152
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my string will be this to this.

153
00:09:10,080 --> 00:09:12,360
OK, so basically my string will be.

154
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So starting from B and it will add and da da da.

155
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OK, so basically here before the character, see so what I can do.

156
00:09:21,490 --> 00:09:28,510
So if I am removing basically B start, so if I'm removing start, then I have to check the palindrome

157
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from start plus one to end.

158
00:09:31,730 --> 00:09:38,120
OK, so you can see and it's pointing towards the C so the first cases start to start.

159
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So I have to check the string from start to end and if I'm deleting the end, so I am deleting and then

160
00:09:44,770 --> 00:09:47,020
I have to check the string from start plus one.

161
00:09:47,980 --> 00:09:50,590
So from start to end of minus one.

162
00:09:52,090 --> 00:09:58,960
OK, so I have two cases, first cases, check the string from start plus one to end.

163
00:10:00,220 --> 00:10:03,470
Now, the second case is so here I start.

164
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OK, so I have deleted start and the second cases start to and minus one.

165
00:10:10,990 --> 00:10:17,110
So here I am deleting and OK, so if either of them returns.

166
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True.

167
00:10:18,390 --> 00:10:25,920
If one of them returns true, then my output will be true, OK, if either dissident, true or dissident

168
00:10:25,920 --> 00:10:30,930
true, my output will become true, either one of them should return true if both of them return false.

169
00:10:31,260 --> 00:10:37,710
So if this is returning false and this is also returning false, then my output will be false.

170
00:10:37,740 --> 00:10:39,390
Otherwise, the output will be true.

171
00:10:40,130 --> 00:10:42,430
OK, so I hope you understood the question.

172
00:10:42,450 --> 00:10:44,940
Now let us write the code, ok.

173
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So let's then let's rename it to the name of this thing is a OK, so first of all, we are just writing

174
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the simple palindrome function.

175
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OK, so.

176
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The start will be zero.

177
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What will be and so it will be basically adult size, minus one.

178
00:11:10,480 --> 00:11:16,160
OK, and no simple condition will start is less than articles to end.

179
00:11:16,780 --> 00:11:19,970
So what I have to do so first of all, let's check.

180
00:11:20,050 --> 00:11:20,800
So if.

181
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If this start is not close to end.

182
00:11:28,690 --> 00:11:33,830
So I start to question what I have to do, so I have to do some work I have to handle to get it.

183
00:11:33,880 --> 00:11:35,970
OK, so two cases will be there.

184
00:11:37,190 --> 00:11:41,450
Otherwise, I'm going to do start plus, plus and minus minus.

185
00:11:41,910 --> 00:11:46,020
OK, and finally, if we are not building any character.

186
00:11:46,040 --> 00:11:48,170
OK, so this thing is basically a palindrome.

187
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String is.

188
00:11:50,100 --> 00:11:51,210
Already palindrome.

189
00:11:56,370 --> 00:11:59,790
So everything is already a palindrome then we can return to.

190
00:12:01,270 --> 00:12:11,830
OK, now I have to handle two cases, so either delayed start so we can start, then I have to check

191
00:12:11,830 --> 00:12:12,160
for.

192
00:12:13,210 --> 00:12:14,740
I have to check for a string.

193
00:12:16,500 --> 00:12:19,860
I have to check for string starting from start plus one.

194
00:12:21,210 --> 00:12:29,820
The end and the second cases delayed the end, so delayed and then I have to check for the string.

195
00:12:32,950 --> 00:12:35,860
So I have to check for the string starting from start.

196
00:12:37,220 --> 00:12:38,480
Two and a minus one.

197
00:12:39,260 --> 00:12:44,090
OK, so these are the two cases that we need to handle here, so let's try to function first.

198
00:12:45,820 --> 00:12:48,550
So I am writing a function to bool.

199
00:12:49,530 --> 00:12:56,250
Check now this check function is taking a string as input string, and it will take a start and end.

200
00:12:56,540 --> 00:13:00,510
OK, so it is taking start and end.

201
00:13:02,320 --> 00:13:06,790
Now, I will write this simple code, so we'll start this list in articles to end.

202
00:13:08,200 --> 00:13:14,410
Would I have to do so if I start is not going to offend?

203
00:13:16,480 --> 00:13:18,100
Then I congratulated Penfold's.

204
00:13:19,920 --> 00:13:26,520
OK, otherwise, I am going to start plus, plus and minus minus, and here I am returning to.

205
00:13:32,430 --> 00:13:33,300
So basically.

206
00:13:35,160 --> 00:13:39,960
So basically what this function will do, so it will take a string as input, it will take the starting

207
00:13:39,960 --> 00:13:41,580
point, it will take the ending point.

208
00:13:41,640 --> 00:13:44,130
OK, so suppose I have a very long string.

209
00:13:44,670 --> 00:13:50,850
So I have given this starting point and I have given the ending point so dysfunctional this function

210
00:13:50,850 --> 00:13:52,500
will check this part of the string.

211
00:13:53,440 --> 00:13:56,070
It will only this part of the string for palindrome.

212
00:13:56,100 --> 00:14:02,340
OK, so if it is not a palindrome, if this part is not a palindrome, it will return false if this

213
00:14:02,340 --> 00:14:03,940
part is a total return.

214
00:14:03,960 --> 00:14:04,220
True.

215
00:14:04,410 --> 00:14:08,310
OK, so this check function, it will not check the complete string.

216
00:14:08,310 --> 00:14:10,750
It will only check a part of the string, OK.

217
00:14:11,160 --> 00:14:12,930
It will only check a part of the string.

218
00:14:15,380 --> 00:14:21,410
So what I have to do, so I have two cases, two first cases I'm calling the function check.

219
00:14:22,900 --> 00:14:29,050
String is a and let's say I am deleting as so I will pass Astarte plus one to end.

220
00:14:29,380 --> 00:14:34,180
Now the second case is let's call the check function.

221
00:14:34,450 --> 00:14:36,250
String is a now.

222
00:14:36,610 --> 00:14:38,140
I will delete the end.

223
00:14:38,170 --> 00:14:40,810
So I'm deleting and so I will pass and minus one.

224
00:14:41,900 --> 00:14:49,790
So if either of them, either this one or I did this one, if either of them returns true, I will return

225
00:14:49,790 --> 00:14:50,060
to.

226
00:14:52,420 --> 00:14:53,440
In the aspart.

227
00:14:55,060 --> 00:14:56,200
I will return false.

228
00:14:58,380 --> 00:15:00,220
So basically, what is the meaning here?

229
00:15:00,750 --> 00:15:04,590
So when everything falls, that means after deleting one character.

230
00:15:07,160 --> 00:15:10,590
After deleting one character, we are not able to make the string palindrome.

231
00:15:10,610 --> 00:15:14,990
OK, so we are unable to obtain.

232
00:15:16,460 --> 00:15:18,140
Apelin lobstering, OK?

233
00:15:19,830 --> 00:15:24,960
So we after building one character, we are unable to obtain a palindrome string, then I can return

234
00:15:24,960 --> 00:15:25,350
false.

235
00:15:25,500 --> 00:15:29,400
OK, so this is very simple code and all this stuff called.

236
00:15:35,340 --> 00:15:36,270
Knowledge summit.

237
00:15:40,630 --> 00:15:45,490
OK, so our goal is working fine now let us discuss the time and the space complexity.

238
00:15:46,240 --> 00:15:52,990
So basically the time complexities are there often and the space complexities big of one.

239
00:15:53,110 --> 00:15:56,150
OK, so this is the time and the space complexity for this problem.

240
00:15:56,740 --> 00:16:02,320
So if you have any doubt in this question, you can ask me, OK, so this question was very simple.

241
00:16:02,330 --> 00:16:06,040
We are just like it is just a modification of the palindrome problem.

242
00:16:06,050 --> 00:16:09,190
OK, simple modification of Ballenden problem.

243
00:16:10,110 --> 00:16:14,640
OK, so if you have any doubt, please ask me, OK, thank you.