Pku3764 The xor-longest Path

时间限制:1s      空间限制:64MB

题目描述

给定一棵n个点的带权树,求树上最长的异或和路径


输入格式

The input contains several test cases. The first line of each test case contains an integer n(1<=n<=100000), The following n-1 lines each contains three integers u(0 <= u < n),v(0 <= v < n),w(0 <= w < 2^31), which means there is an edge between node u and v of length w.


输出格式

For each test case output the xor-length of the xor-longest path.


样例输入

4
1 2 3
2 3 4
2 4 6

样例输出

7


提示

The xor-longest path is 1->2->3, which has length 7 (=3 ⊕ 4) 注意:结点下标从1开始到N....


题目来源

鸣谢陶文博