以 513. 最长回文子序列为例
int longestPalindromeSubseq(string s) {
int n = s.length(), f[n][n];
memset(f, 0, sizeof(f));
for (int i = n - 1; i >= 0; --i){
f[i][i] = 1;
for (int j = i + 1; j < n; ++j){
f[i][j] = s[i] == s[j] ? f[i+1][j-1] + 2 : max(f[i+1][j], f[i][j-1]);
}
}
return f[0][n-1];
}