【treap tree】 HDOJ 3726 && LA 5031 && UVA 1479 Graph and Queries

在线转离线。。先构建出最终的图，然后逆着处理。。不过有几个要注意的地方。。。答案超int，要用long long。。逆着处理的时候C操作要反着操作。。求第k大的时候，k可能是0或负数，也可能超过集合元素个数。。

#include <iostream>  
#include <queue>  
#include <stack>  
#include <map>  
#include <set>  
#include <bitset>  
#include <cstdio>  
#include <algorithm>  
#include <cstring>  
#include <climits>  
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 20005
#define eps 1e-10
#define mod 1000000009
#define INF 99999999  
#define lowbit(x) (x&(-x))  
//#define lson o<<1, L, mid  
//#define rson o<<1 | 1, mid+1, R  
typedef long long LL;
//typedef int LL;
using namespace std;

int value[maxn], n, m;
char s[100];
struct Edge
{
	int u, v, done;
}edges[60005];
struct opr
{
	int kk, x, y;
}op[1000005];
int opp, cnt;
LL ans;
int f[maxn], num[maxn];
struct node
{
	int key, v, s;
	struct node *ch[2];
	int cmp(int x) const {
		if(x == v) return -1;
		return x < v ? 0 : 1;
	}
	void maintain(void)
	{
		s = ch[0]->s + ch[1]->s + 1;
	}
}*null, *root[maxn];

void read(void)
{
	opp = 0;
	for(int i = 1; i <= n; i++) scanf("%d", &value[i]);
	for(int i = 1; i <= m; i++) scanf("%d%d", &edges[i].u, &edges[i].v), edges[i].done = 0;
	while(scanf("%s", s)!=EOF) {
		if(s[0] == 'E') break;
		if(s[0] == 'D') op[opp].kk = 0, scanf("%d", &op[opp++].x), edges[op[opp-1].x].done = 1;
		if(s[0] == 'Q') op[opp].kk = 1, scanf("%d%d", &op[opp].x, &op[opp].y), opp++;
		if(s[0] == 'C') op[opp].kk = 2, scanf("%d%d", &op[opp].x, &op[opp].y), swap(op[opp].y, value[op[opp].x]), opp++;
	}
}
void init(void)
{
	int i;
	ans = cnt = 0;
	for(i = 0; i < maxn; i++) num[i] = 1;
	for(i = 0; i < maxn; i++) f[i] = i;
	null = new node;
	null->s = null->v = 0;
	for(i = 0; i <= n; i++) {
		root[i] = new node;
		root[i] = null;
	}
}
int find(int x)
{
	return f[x] == x ? f[x] : find(f[x]);
}
void rotate(node* &o, int d)
{
	node *k = o->ch[d^1]; o->ch[d^1] = k->ch[d], k->ch[d] = o;
	o->maintain(), k->maintain(), o = k;
}
void insert(node* &o, int x)
{
	if(o == null) {
		o = new node;
		o->key = rand(), o->v = x;
		o->s = 1, o->ch[0] = o->ch[1] = null;
		return;
	}
	int d = x < o->v ? 0 : 1;
	insert(o->ch[d], x);
	if(o->key < o->ch[d]->key) rotate(o, d^1);
	o->maintain();
}
void remove(node* &o, int x)
{
	int d = o->cmp(x);
	if(d == -1) {
		if(o->ch[0] != null && o->ch[1] != null) {
			int d2 = (o->ch[0]->key > o->ch[1]->key ? 1 : 0);
			rotate(o, d2), remove(o->ch[d2], x);
		}
		else {
			node *u = o;
			if(o->ch[0] == null) o = o->ch[1];
			else o = o->ch[0];
			delete u;
		}
	}
	else remove(o->ch[d], x);
	if(o != null) o->maintain();
}
int kth(node *o, int k)
{
	if(o == null || o->s < k || k <= 0) return 0;
	if(o->ch[1]->s >= k) return kth(o->ch[1], k);
	if(o->ch[1]->s + 1 == k) return o->v;
	return kth(o->ch[0], k - o->ch[1]->s - 1);
}
void debug(node* o)
{
	printf("FSDF  %d\n", o->v);
	if(o->ch[0] != null) debug(o->ch[0]);
	if(o->ch[1] != null) debug(o->ch[1]);
}
void removetree(node* &o, node* &p)
{
	if(o == null) return;
	if(o->ch[0] != null) removetree(o->ch[0], p);
	if(o->ch[1] != null) removetree(o->ch[1], p);
	insert(p, o->v);
	delete o;
}
void updata(int a, int v)
{
	int aa = find(a);
	remove(root[aa], value[a]);
	value[a] = v;
	insert(root[aa], value[a]);
}
void query(int a, int k)
{
	int aa = find(a);
	ans += kth(root[aa], k);
}
void merge(int a, int b)
{
	int aa = find(a), bb = find(b);
	if(aa == bb) return;
	if(num[aa] > num[bb]) {
		removetree(root[bb], root[aa]);
		f[bb] = aa, num[aa] += num[bb], num[bb] = 0;
		root[bb] = null;
	}
	else {
		removetree(root[aa], root[bb]);
		f[aa] = bb, num[bb] += num[aa], num[aa] = 0;
		root[aa] = null;
	}
}
void work(void)
{
	int i, aa, bb;
	for(i = 1; i <= m; i++)
		if(!edges[i].done) {
			aa = find(edges[i].u);
			bb = find(edges[i].v);
			if(aa != bb) {
				if(aa > bb) f[aa] = bb, num[bb] += num[aa], num[aa] = 0;
				else f[bb] = aa, num[aa] += num[bb], num[bb] = 0;
			}
		}
	for(i = 1; i <= n; i++) insert(root[find(i)], value[i]);
	for(i = opp-1; i >= 0; i--) {
		if(op[i].kk == 0) merge(edges[op[i].x].u, edges[op[i].x].v);
		if(op[i].kk == 1) query(op[i].x, op[i].y), cnt++;
		if(op[i].kk == 2) updata(op[i].x, op[i].y);
	}
}
int main(void)
{
	int _ = 0;
	while(scanf("%d%d", &n, &m), n!=0 || m!=0) {
		init();
		read();
		work();
		printf("Case %d: %.6f\n", ++_, ans/(double)cnt);
	}
	return 0;
}