[BZOJ3545][ONTAK2010]Peaks

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <stack>
#include <vector>
#include <queue>
#include <cstring>
#include <string>
#include <map>
#include <set>
using namespace std;

const int BufferSize = 1 << 16;
char buffer[BufferSize], *Head, *Tail;
inline char Getchar() {
	if(Head == Tail) {
		int l = fread(buffer, 1, BufferSize, stdin);
		Tail = (Head = buffer) + l;
	}
	return *Head++;
}
int read() {
	int x = 0, f = 1; char c = Getchar();
	while(!isdigit(c)){ if(c == ‘-‘) f = -1; c = Getchar(); }
	while(isdigit(c)){ x = x * 10 + c - ‘0‘; c = Getchar(); }
	return x * f;
}

#define maxn 100010
#define maxm 500010
struct Node {
	int v, r, siz;
	Node() {}
	Node(int _, int __): v(_), r(__) {}
} ns[maxn];
int ToT, fa[maxn], ch[maxn][2], rec[maxn], rcnt;
int getnode() {
	if(rcnt) {
		int o = rec[rcnt--];
		fa[o] = ch[o][0] = ch[o][1] = 0;
		return o;
	}
	return ++ToT;
}
void maintain(int o) {
	ns[o].siz = 1;
	for(int i = 0; i < 2; i++) if(ch[o][i])
		ns[o].siz += ns[ch[o][i]].siz;
	return ;
}
void rotate(int u) {
	int y = fa[u], z = fa[y], l = 0, r = 1;
	if(z) ch[z][ch[z][1]==y] = u;
	if(ch[y][1] == u) swap(l, r);
	fa[u] = z; fa[y] = u; fa[ch[u][r]] = y;
	ch[y][l] = ch[u][r]; ch[u][r] = y;
	maintain(y); maintain(u);
	return ;
}
void insert(int& o, int v) {
	if(!o) {
		ns[o = getnode()] = Node(v, rand());
		return maintain(o);
	}
	bool d = v > ns[o].v;
	insert(ch[o][d], v); fa[ch[o][d]] = o;
	if(ns[ch[o][d]].r > ns[o].r) {
		int t = ch[o][d];
		rotate(t); o = t;
	}
	return maintain(o);
}
int val[maxn], cntv;
void recycle(int& o) {
	if(!o) return ;
	recycle(ch[o][0]); recycle(ch[o][1]);
	rec[++rcnt] = o; val[++cntv] = ns[o].v; fa[o] = 0; o = 0;
	return ;
}
void merge(int& u, int& v) {
//	printf("merge(%d, %d)\n", u, v);
	cntv = 0; recycle(v);
//	printf("vals: "); for(int i = 1; i <= cntv; i++) printf("%d%c", val[i], i < cntv ? ‘ ‘ : ‘\n‘);
	for(int i = 1; i <= cntv; i++) insert(u, val[i]);
	return ;
}
int Find(int o, int k) {
	if(!o) return -1;
	int rs = ch[o][1] ? ns[ch[o][1]].siz : 0;
	if(k == rs + 1) return ns[o].v;
	if(k < rs + 1) return Find(ch[o][1], k);
	return Find(ch[o][0], k - rs - 1);
}

int pa[maxn], rt[maxn];
int findset(int x) { return x == pa[x] ? x : pa[x] = findset(pa[x]); }

struct Edge {
	int a, b, c;
	Edge() {}
	Edge(int _1, int _2, int _3): a(_1), b(_2), c(_3) {}
	bool operator < (const Edge& t) const { return c < t.c; }
} es[maxm];
struct Que {
	int u, x, k, id;
	Que() {}
	Que(int _1, int _2, int _3, int _4): u(_1), x(_2), k(_3), id(_4) {}
	bool operator < (const Que& t) const { return x < t.x; }
} qs[maxm];
int ans[maxm];

int main() {
	int n = read(), m = read(), q = read();
	for(int i = 1; i <= n; i++) {
		int v = read();
		pa[i] = i; insert(rt[i], v);
	}
	for(int i = 1; i <= m; i++) {
		int a = read(), b = read(), c = read();
		es[i] = Edge(a, b, c);
	}
	sort(es + 1, es + m + 1);
	for(int i = 1; i <= q; i++) {
		int u = read(), x = read(), k = read();
		qs[i] = Que(u, x, k, i);
	}
	sort(qs + 1, qs + q + 1);
	
//	for(int i = 1; i <= m; i++) printf("Edge: %d %d %d\n", es[i].a, es[i].b, es[i].c);
//	for(int i = 1; i <= q; i++) printf("Que: %d %d %d\n", qs[i].u, qs[i].x, qs[i].k);
	
	for(int i = 1, e = 1; i <= q; i++) {
		while(e <= m && es[e].c <= qs[i].x) {
			int u = findset(es[e].a), v = findset(es[e].b);
//			printf("%d: %d(%d) %d(%d) %d\n", e, u, es[e].a, v, es[e].b, findset(8));
			if(u != v) {
				if(ns[rt[u]].siz < ns[rt[v]].siz) swap(u, v);
				merge(rt[u], rt[v]);
				pa[v] = u;
			}
			e++;
		}
		ans[qs[i].id] = Find(rt[findset(qs[i].u)], qs[i].k);
	}
	
	for(int i = 1; i <= q; i++) printf("%d\n", ans[i]);
	
	return 0;
}