Day33 动态规划2 | LeetCode 62. 不同路径, 63. 不同路径 II

LeetCode 62. 不同路径

class Solution {
public:
    int uniquePaths(int m, int n) {
        vector<vector<int>> dp(m, vector<int>(n, 1));
        for (int i = 1; i < m; i++){
            for (int j = 1; j < n; j++){
                dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        }
        return dp[m - 1][n - 1];
    }
};

LeetCode 63. 不同路径 II

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));
        for (int i = 0; i < m; i++){
            if (obstacleGrid[i][0] != 1){
                dp[i][0] = 1;
            }else {
                break;
            }
        }
        for (int j = 0; j < n; j++){
            if (obstacleGrid[0][j] != 1){
                dp[0][j] = 1;
            }else {
                break;
            }
        }
        for (int i = 1; i < m; i++){
            for (int j = 1; j < n; j++){
                if (obstacleGrid[i][j] == 1){
                    //遇到障碍
                    dp[i][j] = 0;
                }else {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
        }

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




    }
};