Triangle

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Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.

For example, given the following triangle

[     [2],    [3,4],   [6,5,7],  [4,1,8,3]]

The minimum path sum from top to bottom is 11 (i.e., 2 + 3 + 5 + 1 = 11).

Note:

Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows in the triangle.

分析：

dp：

http://blog.csdn.net/linhuanmars/article/details/23230657
巧妙的自底向上动态规划，我是想不出来o(╯□╰)o

public class Solution {    public int minimumTotal(List<List<Integer>> triangle) {    if(triangle.size() == 0)        return 0;    int[] res = new int[triangle.size()];    for(int i=0;i<triangle.size();i++)    {        res[i] = triangle.get(triangle.size()-1).get(i);    }    for(int i=triangle.size()-2;i>=0;i--)    {        for(int j=0;j<=i;j++)        {            res[j] = Math.min(res[j],res[j+1])+triangle.get(i).get(j);         }    }    return res[0];}}

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