LeetCode/uniquePathsWithObstacles.cpp at main · zxk-creator/LeetCode · GitHub

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#include <vector>

using namespace std;

class Solution
{
public:
    int uniquePathsWithObstacles(vector<vector<int>> &obstacleGrid)
    {
        if (obstacleGrid[0][0] == 1 || obstacleGrid.back().back() == 1) return 0;

        // 扩容
        vector<vector<int>> res(obstacleGrid.size(),vector<int>(obstacleGrid[0].size()));
        bool bShouldSetAsZero = false;
        // 首先还是初始化第一横排和第一竖排
        for (int i = 0;i < res[0].size();i++)
        {
            if (bShouldSetAsZero)
            {
                res[0][i] = 0;
                continue;
            }
            if (obstacleGrid[0][i] == 1)
            {
                res[0][i] = 0;
                bShouldSetAsZero = true;
            }
            else
            {
                res[0][i] = 1;
            }
        }
        bShouldSetAsZero = false;
        // 竖排
        for (int i = 0;i < res.size();i++)
        {
            if (bShouldSetAsZero)
            {
                res[i][0] = 0;
                continue;
            }
            if (obstacleGrid[i][0] == 1)
            {
                res[i][0] = 0;
                bShouldSetAsZero = true;
            }
            else
            {
                res[i][0] = 1;
            }
        }

        for (int i = 1;i < res.size();i++)
        {
            for (int j = 1;j < res[0].size();j++)
            {
                if (obstacleGrid[i][j] == 1)
                {
                    res[i][j] = 0;
                    continue;
                }
                else
                {
                    res[i][j] = res[i - 1][j] + res[i][j - 1];
                }
            }
        }

        return res.back().back();
    }
};