leetcode_63_UniquePath2

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