63. Unique Paths II

题目链接

https://leetcode.com/problems/unique-paths-ii/submissions/

解题思路

简单dp，直接看代码

代码

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int m = obstacleGrid.size();
        if (m == 0) {
            return 0;
        }
        int n = obstacleGrid[0].size();
        vector<vector<long>> dp(m, vector<long>(n, 0));
        
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (obstacleGrid[i][j] == 1) {
                    dp[i][j] = 0;
                } else if (i == 0 && j == 0) {
                    dp[i][j] = 1;
                } else if (i == 0) {
                    dp[i][j] = dp[i][j - 1];
                } else if (j == 0) {
                    dp[i][j] = dp[i - 1][j];
                } else {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
        }
        return dp[m - 1][n - 1];
    }
};