[leetcode]Unique Paths

class Solution {public:    int uniquePaths(int m, int n) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        vector<vector<int>> f(m, vector<int>(n, 1));                for(int i = 1; i < m; i++){            for(int j = 1; j < n; j++){                f[i][j] = f[i-1][j] + f[i][j-1];            }        }        return f[m-1][n-1];    }};