hdu 6035 Colorful Tree
Colorful Tree
Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 182 Accepted Submission(s): 46
Problem Description
There is a tree with
n nodes, each of which has a type of color represented by an integer, where the color of node
i is
ci.
The path between each two different nodes is unique, of which we define the value as the number of different colors appearing in it.
Calculate the sum of values of all paths on the tree that has n(n−1)2 paths in total.
The path between each two different nodes is unique, of which we define the value as the number of different colors appearing in it.
Calculate the sum of values of all paths on the tree that has n(n−1)2 paths in total.
Input
The input contains multiple test cases.
For each test case, the first line contains one positive integers n, indicating the number of node. (2≤n≤200000)
Next line contains n integers where the i-th integer represents ci, the color of node i. (1≤ci≤n)
Each of the next n−1 lines contains two positive integers x,y (1≤x,y≤n,x≠y), meaning an edge between node x and node y.
It is guaranteed that these edges form a tree.
For each test case, the first line contains one positive integers n, indicating the number of node. (2≤n≤200000)
Next line contains n integers where the i-th integer represents ci, the color of node i. (1≤ci≤n)
Each of the next n−1 lines contains two positive integers x,y (1≤x,y≤n,x≠y), meaning an edge between node x and node y.
It is guaranteed that these edges form a tree.
Output
For each test case, output "
Case #x: y" in one line (without quotes), where
x indicates the case number starting from
1 and
y denotes the answer of corresponding case.
Sample Input
3 1 2 1 1 2 2 3 6 1 2 1 3 2 1 1 2 1 3 2 4 2 5 3 6
Sample Output
Case #1: 6 Case #2: 29
Source
2017 Multi-University Training Contest - Team 1
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思路：现场没想出来，看题解后想了好久终于写了出来。问题等价于算每种颜色有多少条路径经过。又等价于所有情况-每一种颜色有多少条路径没有经过这种颜色。然后这个是可以O（n）跑出来的。跑的时候维护几个数值。size[i]以该节点为根的树的节点数。sum[i]比较难说明，具体看代码领悟。。下面给代码：
//#pragma comment(linker, "/STACK:102400000,102400000")
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include