# LeetCode - 0063. Unique Paths II
### 題目網址：https://leetcode.com/problems/unique-paths-ii/
###### tags: `LeetCode` `Medium` `動態規劃（Dynamic Programming）`

/*
    -LeetCode format-
    Problem: 63. Unique Paths II
    Difficulty: Medium
    
    by Inversionpeter
*/



int ways[101][101];

static const auto Initialize = []{
    ios::sync_with_stdio(false); cout.tie(nullptr);
    return nullptr;
}();


class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int rows = obstacleGrid.size(), columns = obstacleGrid[0].size();
        memset(ways, 0, sizeof(ways));
        ways[0][0] = (obstacleGrid[0][0] ? 0 : 1);
        for (int i = 1; i < rows; ++i)
            ways[i][0] = (obstacleGrid[i][0] ? 0 : ways[i - 1][0]);
        for (int i = 1; i < columns; ++i)
            ways[0][i] = (obstacleGrid[0][i] ? 0 : ways[0][i - 1]);
        for (int i = 1; i < rows; ++i)
            for (int j = 1; j < columns; ++j)
                if (!obstacleGrid[i][j])
                    ways[i][j ] = ways[i][j - 1] + ways[i - 1][j];
        return ways[rows - 1][columns - 1];
    }
};