HDU 3938 Portal【並查集+upper_bound(第四個引數)】

DTL66發表於2016-11-13
並查集

Portal

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 1459    Accepted Submission(s): 745


Problem Description
ZLGG found a magic theory that the bigger banana the bigger banana peel .This important theory can help him make a portal in our universal. Unfortunately, making a pair of portals will cost min{T} energies. T in a path between point V and point U is the length of the longest edge in the path. There may be lots of paths between two points. Now ZLGG owned L energies and he want to know how many kind of path he could make.
 

Input
There are multiple test cases. The first line of input contains three integer N, M and Q (1 < N ≤ 10,000, 0 < M ≤ 50,000, 0 < Q ≤ 10,000). N is the number of points, M is the number of edges and Q is the number of queries. Each of the next M lines contains three integers a, b, and c (1 ≤ a, b ≤ N, 0 ≤ c ≤ 10^8) describing an edge connecting the point a and b with cost c. Each of the following Q lines contain a single integer L (0 ≤ L ≤ 10^8).
 

Output
Output the answer to each query on a separate line.
 

Sample Input
10 10 10
7 2 1
6 8 3
4 5 8
5 8 2
2 8 9
6 4 5
2 1 5
8 10 5
7 3 7
7 8 8
10
6
1
5
9
1
8
2
7
6





 



Sample Output




36
13
1
13
36
1
36
2
16
13














AC程式碼：


#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<map>

using namespace std;

const int MAXN=1e4+11;
int fa[MAXN];

struct Edge{
	int u,v,w;
}e[50011];
int ans[50011],s[50011];

bool cmp(Edge a,Edge b) {
	return a.w<b.w;
}
int Find(int x) {
	return x==fa[x]?x:fa[x]=Find(fa[x]);
}
int main()
{
    int N,M,Q;
	while(~scanf("%d%d%d",&N,&M,&Q)) {
		for(int i=1;i<=M;++i) {
			scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);
		}
		sort(e+1,e+M+1,cmp);
		for(int i=1;i<=N;++i) {
		    fa[i]=i; s[i]=1;	
		}
		ans[0]=0;
		for(int i=1;i<=M;++i) {
		    int x=Find(e[i].u);
		    int y=Find(e[i].v);
		    ans[i]=ans[i-1];
		    if(x!=y) {
		        ans[i]+=s[x]*s[y];
		        fa[x]=y;  s[y]+=s[x];  
			}
		}
		while(Q--) {
		//	puts("");
			Edge q; scanf("%d",&q.w);
			int loc=upper_bound(e+1,e+M+1,q,cmp)-e;
			if(e[loc].w==q.w) printf("%d\n",ans[loc]);
			else printf("%d\n",ans[loc-1]);
		}
	} 
	return 0;
 } 


            




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