Unique Paths II

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int height = obstacleGrid.size();
        int width = obstacleGrid[0].size();
        vector<vector<int>> result(height,vector<int>(width));
        if(obstacleGrid[0][0] == 1 || obstacleGrid[height-1][width-1] == 1)
            return 0;
        for(int i = 0;i < height;i++){
            for(int j = 0;j < width;j++){
                if(obstacleGrid[i][j] == 1)
                    result[i][j] = 0;
                else
                    result[i][j] = -1;
            }
        }
        result[0][0] = 1;
        for(int i = 0;i < height;i++){
            for(int j = 0;j < width;j++){
                if(i == 0 && j == 0)
                    continue;
                if(result[i][j] == 0)
                    continue;
                if(i != 0 && j != 0)
                    result[i][j] = result[i][j-1] + result[i-1][j];
                else if(i == 0)
                    result[i][j] = result[i][j-1];
                else
                    result[i][j] = result[i-1][j];
            }
        }
        return result[height-1][width-1];
    }
};