64. Minimum Path Sum

题目：

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.

 

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 Array Dynamic Programming

 

链接： http://leetcode.com/problems/minimum-path-sum/

5/20/2017

注意第7，9，12行

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