Longest Palindromic Subsequence Dynamic Programming

Question

The link of the question is https://practice.geeksforgeeks.org/problems/longest-palindromic-subsequence/0 . May I know whether my approach is a correct solution using Dynamic Programming . The code is :

#include <bits/stdc++.h>
using namespace std;
int main() {
    //code
    int t;
    cin>>t;
    while(t--){
        string a;
        cin>>a;
        int l = a.length();
        int dp[l][l] = {0};
        for(int i = 0; i<l; i++){
            for(int j = 0; j<l; j++){
                if(i==j){
                    dp[i][i] = 1;
                }
            }
        }
        for(int i = 1; i<l; i++){
            int r = 0;
            int c = i;
            while(r<l and c<l){
                if(a[r]==a[c]){
                    dp[r][c] = dp[r+1][c-1]+2;
                }
                else{
                    dp[r][c] = max(dp[r+1][c], dp[r][c-1]);
                }
                r++;
                c++;
            }
        }
        cout<<dp[0][l-1]<<endl;
    }
    return 0;
}

where t is the number of test cases and a is the input string . We have to determine the length of the longest palindromic subsequence .