Description

Submission

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        if(obstacleGrid[0][0] == 1) return 0;
        int nRow = obstacleGrid.size();
        int nCol = obstacleGrid[0].size();
        vector<vector<int>> dp(nRow, vector<int>(nCol, 0));
        bool isBlocked = false;
        for(int i = 0; i < nRow; ++i) {
            if(obstacleGrid[i][0] == 1) isBlocked = true;
            if(!isBlocked) dp[i][0] = 1;
            else dp[i][0] = 0;
        }
        isBlocked = false;
        for(int j = 1; j < nCol; ++j) {
            if(obstacleGrid[0][j] == 1) isBlocked = true;
            if(!isBlocked) dp[0][j] = 1;
            else dp[0][j] = 0;
        }
        
        for(int i = 1; i < nRow; ++i) {
            for(int j = 1; j < nCol; ++j) {
                if(obstacleGrid[i][j] == 1) continue;
                dp[i][j] = dp[i-1][j] + dp[i][j-1];
            }
        }
        return dp[nRow-1][nCol-1];
    }
};

Submission 210625

class Solution {

public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        int m = obstacleGrid.size();
        int n = obstacleGrid[0].size();
        vector<vector<int>> dp(m, vector<int>(n, 0));

        dp[0][0] = 1;

        for(int i = 0; i < m; ++i) {
            for(int j = 0; j < n; ++j) {
                if(obstacleGrid[i][j]) {
                    dp[i][j] = 0;
                    continue;
                }
                if(i != 0) dp[i][j] += dp[i-1][j];
                if(j != 0) dp[i][j] += dp[i][j-1];
            }
        }

        return dp[m-1][n-1];
    }
};