The xor-longest Path

The xor-longest Path

Time Limit: 2000MS		Memory Limit: 65536K
Total Submissions: 3875		Accepted: 850

Description

In an edge-weighted tree, the xor-length of a path p is defined as the xor sum of the weights of edges on p:

⊕ is the xor operator.

We say a path the xor-longest path if it has the largest xor-length. Given an edge-weighted tree with n nodes, can you find the xor-longest path? 　

Input

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.

Output

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

Sample Input

4
0 1 3
1 2 4
1 3 6

Sample Output

7

Hint

The xor-longest path is 0->1->2, which has length 7 (=3 ⊕ 4)

　　這道題由於沒看到多組數據，WA了很久，題目比較簡單，但是運用了a xor b= a xor c xor b xor c，這應該是解異或題目常用的技巧。 

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转载于:https://www.cnblogs.com/mhy12345/p/3970458.html