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"Longest Palindromic Substring"

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Original file line number	Diff line number	Diff line change
@@ -295,7 +295,7 @@ The `☢` means that you need to have a LeetCode Premium Subscription.
`295`	`295`	`\| 8 \| [String to Integer (atoi)] \| [C](src/8.c) \|`
`296`	`296`	`\| 7 \| [Reverse Integer] \| [C](src/7.c) \|`
`297`	`297`	`\| 6 \| [ZigZag Conversion] \| [C](src/6.c) \|`
`298`		`-\| 5 \| [Longest Palindromic Substring] \| \|`
	`298`	`+\| 5 \| [Longest Palindromic Substring] \| [C++](src/5.cpp) \|`
`299`	`299`	`\| 4 \| [Median of Two Sorted Arrays] \| \|`
`300`	`300`	`\| 3 \| [Longest Substring Without Repeating Characters] \| \|`
`301`	`301`	`\| 2 \| [Add Two Numbers] \| [C](src/2.c) \|`

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`@@ -0,0 +1,50 @@`
	`1`	`+#include <iostream>`
	`2`	`+#include <string>`
	`3`	`+#include <cassert>`
	`4`	`+`
	`5`	`+using namespace std;`
	`6`	`+`
	`7`	`+class Solution {`
	`8`	`+public:`
	`9`	`+ string longestPalindrome(string s) {`
	`10`	`+ int n = s.length();`
	`11`	`+ int start = 0, maxLen = 1; // important, cos a single letter is palindrome`
	`12`	`+ int i, j, k ;`
	`13`	`+ for (i = 0; i < n; i++) {`
	`14`	`+ j = i, k = i + 1; //even length`
	`15`	`+ while (j >= 0 && k < n) {`
	`16`	`+ if (s[j] != s[k]) break;`
	`17`	`+ if (k - j + 1 > maxLen) {`
	`18`	`+ start = j;`
	`19`	`+ maxLen = k - j + 1;`
	`20`	`+ }`
	`21`	`+ j--;`
	`22`	`+ k++;`
	`23`	`+ }`
	`24`	`+ j = i - 1, k = i + 1; // odd length`
	`25`	`+ while(j >= 0 && k <= n - 1) {`
	`26`	`+ if (s[j] != s[k]) break;`
	`27`	`+ if (k - j + 1 > maxLen) {`
	`28`	`+ start = j;`
	`29`	`+ maxLen = k - j + 1;`
	`30`	`+ }`
	`31`	`+ j--;`
	`32`	`+ k++;`
	`33`	`+ }`
	`34`	`+ }`
	`35`	`+ return s.substr(start, maxLen);`
	`36`	`+ }`
	`37`	`+};`
	`38`	`+`
	`39`	`+int main() {`
	`40`	`+ string str0 = "aabac";`
	`41`	`+ string str1 = "a";`
	`42`	`+ Solution s;`
	`43`	`+`
	`44`	`+ assert(s.longestPalindrome(str0) == "aba");`
	`45`	`+ assert(s.longestPalindrome(str1) == "a");`
	`46`	`+`
	`47`	`+ printf("all tests passed!\n");`
	`48`	`+`
	`49`	`+ return 0;`
	`50`	`+}`

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