Minimum Path Sum

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;
        int n = grid[0].length;
        if (m <= 0 || n <= 0) {
        	return 0;
        }
        int[][] res = new int[m][n];
        res[0][0] = grid[0][0];
        for (int i = 1; i < m; i++) {
        	res[i][0] = grid[i][0]+res[i-1][0];
        }
        for (int i = 1; i < n; i++) {
        	res[0][i] = res[0][i-1]+grid[0][i];
        }
        for (int i = 1; i < m; i++) {
        	for (int j = 1; j < n; j++) {
        		if (res[i-1][j] < res[i][j-1]) {
        			res[i][j] = res[i-1][j]+grid[i][j];
        		} else {
        			res[i][j] = res[i][j-1]+grid[i][j];
        		}
        	}
        }
        return res[m-1][n-1];
    }
}