【算法】动态规划系列(二)

62.不同路径

代码

class Solution {
  
    public static int uniquePaths(int m, int n) {
        int[][] dp = new int[m][n];
        //初始化
        for (int i = 0; i < m; i++) {
            dp[i][0] = 1;
        }
        for (int i = 0; i < n; i++) {
            dp[0][i] = 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];
    }
}

63. 不同路径 II

代码

class Solution {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        if(obstacleGrid.length<0){
            return 0;
        }
        int n = obstacleGrid.length;
        int m = obstacleGrid[0].length;
        int[][] dp = new int[n][m];
        // 初始化
        for(int i=0;i