[bzoj 1954]Pku3764 The xor-longest Path
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Pku3764 The xor-longest Path
Time Limit: 1 Sec Memory Limit: 64 MBSubmit: 839 Solved: 369
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Description
![](http://www.lydsy.com/JudgeOnline/images/1954.jpg)
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
1 2 3
2 3 4
2 4 6
1 2 3
2 3 4
2 4 6
Sample Output
7
HINT
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....
对于x,y之间的异或和,等于x到根节点的异或和 ^ y到根节点的异或和。
然后把它们丢到trie里,贪心就好。
代码待补