View Compilation Error

0_0_17303141_29017.cpp: In function 'int main()':
0_0_17303141_29017.cpp:16:6: error: 'dp' was not declared in this scope
      dp[i][j] = 1;
      ^
0_0_17303141_29017.cpp:20:32: error: 'str' was not declared in this scope
     while(t1 >= 0 && t2 < n && str[t1][j] == str[i][t2]) {
                                ^
0_0_17303141_29017.cpp:25:14: error: 'dp' was not declared in this scope
     if(t1 >= dp[i - 1][j + 1] + 1) dp[i][j] = dp[i - 1][j + 1] + 1;
              ^
0_0_17303141_29017.cpp:27:20: error: 'dp' was not declared in this scope
     ans = max(ans, dp[i][j]);
                    ^