/in/foo.cc: In function 'int main()':
/in/foo.cc:11:5: error: 'vector' was not declared in this scope
     vector<vector<long long>> dp(n + 1, vector<long long>(m + 1, 0));
     ^~~~~~
/in/foo.cc:11:19: error: expected primary-expression before 'long'
     vector<vector<long long>> dp(n + 1, vector<long long>(m + 1, 0));
                   ^~~~
/in/foo.cc:12:5: error: 'dp' was not declared in this scope
     dp[1][1] = 2; // 单行单列有 2 种放法：放老虎或不放
     ^~