https://atcoder.jp/contests/dp/tasks/dp_f

void solve(){
    string s;
    string t;
    cin>>s;
    cin>>t;
    int n=s.length();
    int m=t.length();
    vector<vector<int>>dp(n,vector<int>(m));
    int index1=-1;
    for(int i=0;i<m;i++){
        if(s[0]==t[i]){
           index1=i;
           break;
        }
    }
    if(index1!=-1){
    for(int i=index1;i<m;i++){
        dp[0][i]=1;
    }
    }
    int index2=-1;

    for(int i=0;i<n;i++){
        if(t[0]==s[i]){
            index2=i;
            break;
    }

    }
    if(index2!=-1){
        for(int i=index2;i<n;i++){
            dp[i][0]=1;
        }

    }
    for(int i=1;i<n;i++){
        for(int j=1;j<m;j++){
            
                dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
            
            if(s[i]==t[j]){
                dp[i][j]=max(dp[i][j],1+dp[i-1][j-1]);
            }
        }
    }
   string ans="";

     int x=n-1;
     int y=m-1;
     while(x>=0 && y>=0){
        if(s[x]==t[y]){
            ans+=s[x];
            x--;
            y--;

        }else{
            
            if(x>0 && y>0 && dp[x-1][y]>=dp[x][y-1]){
                x--;
            
            }else{
                y--;
            }
        }
    
     }
     if(s[0]==t[0]){
        ans+=s[0];
     }
     reverse(ans.begin(),ans.end());
     cout<<ans<<'\n';

    
}

int main(){
    int t=1;
   
    while(t--){
        solve();
    }

}

In my above code,I am getting some wa.Can anybody help me with problem where am i getting wa.