62. 不同路径

class Solution {
public:
    int uniquePaths(int m, int n) {
        // 二维dp数组
        vector<vector<int> >dp(m, vector<int>(n, 0));
        //初始化
        for (int j = 0; j<n; j++) {
            dp[0][j] = 1;
        }
        for (int i = 0; i< m; i++) {
            dp[i][0] = 1;
        }

        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                dp[i][j] = dp[i][j-1] + dp[i-1][j];
            }
        }

        return dp[m-1][n-1];
        
    }

};

vector初始化方式