64. Minimum Path Sum java solutions

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

 

public class Solution {
    public int minPathSum(int[][] grid) {
        int m = grid.length,n = grid[0].length;
        if(m == 0 || n == 0) return 0;
        int[][] tmp = new int[m][n];
        int cnt = 0;
        for(int i = 0; i < n; i++){
            cnt += grid[0][i];
            tmp[0][i] = cnt;
        }
        cnt = 0;
        for(int i = 0; i < m; i++){
            cnt += grid[i][0];
            tmp[i][0] = cnt;
        }
        
        for(int i = 1;i < m; i++){
            for(int j = 1;j < n; j++){
                tmp[i][j] = Math.min(tmp[i-1][j],tmp[i][j-1]) + grid[i][j];
            }
        }
        return tmp[m-1][n-1];
    }
}

非常自然能想到的解法，一遍AC。