参考题解

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& o) {
        int n = o.size();
        int m = o[0].size();
        if (!n || !m) return 0;
        vector<vector<int>> f(n, vector<int>(m));

        for (int i = 0; i < n; i ++) {
            for (int j = 0; j < m; j ++) {
                if (!o[i][j]) { //当不是障碍物时，进行递推处理，如果是障碍物，则默认初始值0
                    if (!i && !j) f[i][j] = 1;
                    else {
                        if (i) f[i][j] += f[i - 1][j];
                        if (j) f[i][j] += f[i][j - 1];
                    }
                }
            }
        }
        return f[n - 1][m - 1];
    }
};