标签：style blog class code c java
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.
public class Solution { public int minimumTotal(ArrayList<ArrayList<Integer>> triangle) { if(triangle.size()==0) return 0; int len = triangle.size(); int[] re = new int[len]; re[0]=triangle.get(0).get(0); int min=re[0]; for(int i=1;i<triangle.size();i++){ ArrayList<Integer> al = triangle.get(i); int pre = 0; for(int j=0;j<al.size();j++){ if(j==0){ pre=re[0]; re[0]+=al.get(j); min=re[0]; continue; } if(j==al.size()-1){ re[j]=pre+al.get(j); if(re[j]<min) min=re[j]; continue; } int temp = re[j]; re[j]=Math.min(pre, re[j])+al.get(j); pre = temp; if(re[j]<min) min=re[j]; } } return min; } }
【LeetCode】Triangle,布布扣,bubuko.com
标签：style blog class code c java
原文地址：http://www.cnblogs.com/yixianyixian/p/3734028.html
