力扣上比较简答的一道动态规划题目。

      方程：

class Solution {
public:int uniquePaths(int m, int n) {const int M = m;const int N = n;int dp[M][N];memset(dp, 0, sizeof(dp));for (int i = 0; i < m; ++i) dp[i][0] = 1;for (int i = 0; i < n; ++i) dp[0][i] = 1;for (int i = 1; i < m; ++i) {for (int j = 1; j < n; ++j) {dp[i][j] = dp[i - 1][j] + dp[i][j - 1];}}return dp[m-1][n-1];}
};