63. different paths II

Original link ：63. Different paths II

 

solution:

        The standard dp, Just add the judgment of obstacles during initialization and circulation

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));

        // Initialize initial condition 
        bool flag = false;
        for(int i = 0;i < m;i++) {
            if(obstacleGrid[i][0] == 1) flag = true;
            if(!flag) dp[i][0] = 1; 
        }
        
        flag = false;
        for(int j = 0;j < n;j++) {
            if(obstacleGrid[0][j] == 1) flag = true;
            if(!flag) dp[0][j] = 1;
        }

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

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