最小生成树应用解（超时）蓝桥杯2015初赛]灾后重建

#include <iostream>
#include <algorithm>
#include <set>
using namespace std;
constexpr size_t maxn = 2e5+1;
int n, m, q;
struct Edge{
	int from, to, cost;
	Edge(int from, int to, int cost){
		this->from = from;
		this->to = to;
		this->cost = cost;
	}
};
void easy(int,int,int,int);

struct UFNode{
	UFNode* parent;
	UFNode():parent(NULL){}
};

bool cmp(Edge* e1, Edge* e2){
	return e1->cost < e2->cost;
}
Edge* edges[maxn];
UFNode* find(UFNode* p){
	if(p->parent == NULL)return p;
	set<UFNode*> path;
	while(p->parent != NULL){
		path.insert(p);
		p = p->parent;
	}
	auto iter = path.begin();
	while(iter != path.end()){
		(*iter)->parent = p;
		iter++;
	}
	return p;
}
void merge(UFNode* p1, UFNode* p2){
	find(p2)->parent = find(p1);
}
UFNode point[50001];

int main(){

	cin >> n >> m >> q;
	for(int i = 0; i < m; ++ i){
		int a, b, c;
		cin >> a >> b >> c;
		Edge* e = new Edge(a, b, c);
		edges[i] = e;
	}
	//排序 
	sort(edges, edges + m, cmp);
	for(int i = 0; i < q; ++ i){
		int l, r, mod, c;
		cin >> l >> r >> mod >> c;
		easy(l, r, mod, c);
	}
	return 0;
}


void easy(int l, int r, int mod, int c){
	for(int j = 0; j <= n; ++ j){
		point[j].parent = NULL;
	}
	for(int i = 0; i < m; ++ i){
		Edge* pEdge = edges[i];
		int from = pEdge->from;
		int to = pEdge->to;
		int cost = pEdge->cost;

		if(find(&point[from]) == find(&point[to]))//已经在一颗树上
			continue;
		else
			merge(&point[from], &point[to]);
		//if n-1 者最小生成数已经完成
		UFNode* parent = NULL;
		bool isok = true;
		for(int j = l; j <= r; ++ j){
			if(j%mod == c){
				if(parent == NULL){
					parent = find(&point[j]);
				}
				else{
					if(parent != find(&point[j])){
						isok = false;
						break;
					}
				}
			}
		}
		if(isok){
			cout << cost << endl;
			break;
		}
	}
}