63.cpp

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