p64

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LeetCode p64 Minimum Path Sum 题解

1.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.

题意：

从一个矩阵的左上走到右下，找到那和最小的路线的值。

2.解题思路:

见代码，用dfs超时了TUT，以下借鉴了别人的算法思路。。感觉简洁多了。

3.代码

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

		return grid[n - 1][m - 1];
    }
}

4.一些总结：leetcode 100斩 然而还是个渣渣