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// 516. Longest Palindromic Subsequence
#include "leetcode.h"
/*
* given string 's', find the longest palindromic susbsequences
* of length in 's'. a subsequcnes is a sequence that can be derived
* from another sequence by deleting some or no elements without
* changing the order of the remaining elements
*/
class Solution {
public:
int longestPalindromeSubseq(string s) {
int n = s.size();
vector<int> dp(n, 0);
for (int i = n - 1; i >= 0; i--) {
vector<int> new_dp(n, 0);
new_dp[i] = 1;
for (int j = i + 1; j < n; j++) {
if (s[i] == s[j])
new_dp[j] = 2 + dp[j - 1];
else
new_dp[j] = max(dp[j], new_dp[j - 1]);
}
dp = new_dp;
}
return dp[n - 1];
}
};
int main() {
Solution obj;
printf("%d\n", obj.longestPalindromeSubseq("bbbab")); // expect: 4
printf("%d\n", obj.longestPalindromeSubseq("cbbd")); // expect: 2
}
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