LCS.cpp

#include<bits/stdc++.h>
using namespace std;
 int longestCommonSubsequence(string text1, string text2) {
        int n1=text1.size();
        int n2=text2.size();
        vector<vector<int>>dp(2,vector<int>(n2+1));
        for(int i=0;i<2;i++)
        {
            for(int j=0;j<=n2;j++)
            {
                dp[i][j]=0;
            }
        }
        for(int i=1;i<=n1;i++)
        {
            for(int j=1;j<=n2;j++)
            {

                 if(text1[i-1]==text2[j-1])
                {
                    dp[i%2][j]=1+dp[(i+1)%2][j-1];
                }
                else dp[i%2][j]=max(dp[(i+1)%2][j],dp[i%2][j-1]);
            }
        }
        return dp[n1%2][n2];
    }
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        string text1,text2;
        cin>>text1>>text2;
        int answer=longestCommonSubsequence(text1,text2);
        cout<<answer<<endl;
        return 0;
    }
}