Unique Path II

// First solution. This cannot pass larget test.
class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
       if(!obstacleGrid.size() || !obstacleGrid[0].size() || obstacleGrid[0][0])
        return 0;
        else
        return getUniquePath(obstacleGrid.size()-1, obstacleGrid[0].size()-1, obstacleGrid);
        
    }
private:
    int getUniquePath(int i, int j, const vector<vector<int>> &obstacleGrid) {
        assert( i >= 0 && j >= 0);
        if (obstacleGrid[i][j])
            return 0;
        else if ( !i && !j)
            return 1;
        else if(!i)
            return getUniquePath(i, j-1, obstacleGrid);
        else if(!j)
            return getUniquePath(i-1, j, obstacleGrid);
        else
            return getUniquePath(i-1, j, obstacleGrid) + getUniquePath(i, j-1, obstacleGrid);
    }
};

// Second solution. Passed the large test.
class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int> > &obstacleGrid) {
       if(!obstacleGrid.size() || !obstacleGrid[0].size() || obstacleGrid[0][0])
        return 0;
        const int height = obstacleGrid.size();
        const int width = obstacleGrid[0].size();
        int path[height][width];
        for( int i = 0; i < height; ++i)
            for( int j = 0; j < width; ++j) {
                 if (obstacleGrid[i][j])
                    path[i][j] = 0;
                 else if ( !i && !j)
                    path[i][j] = 1;
                 else if(!i)
                    path[i][j] = path[i][j-1];
                 else if(!j)
                    path[i][j] = path[i-1][j];
                 else
                    path[i][j] = path[i-1][j] + path[i][j-1];
            }
        return path[height - 1][width - 1];
    }
};

// Third solution. Optimization space complaxity(Not finished).