HDU 5333 Undirected Graph LCT+BIT Undirected Graph

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我是靠谱客的博主顺心裙子，最近开发中收集的这篇文章主要介绍HDU 5333 Undirected Graph LCT+BIT Undirected Graph，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

链接

Undirected Graph

Time Limit: 5000/2500 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 184 Accepted Submission(s): 38

Problem Description

As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them:

There is an undirected graph with

n vertices and

m edges. Then Yuta does

q operations on this graph. Each operation is described by two integers

L,R (1≤L≤R≤n) and can be split into three steps:

1. Delete all the edges which have at least one vertice outside the range

[L,R] .

2. Yuta wants you to tell him the number of connected component of the graph.

3. Restore the graph.

This task is too hard for Rikka to solve. Can you help her?

Input

There are at most 100 testcases and there are at least 97 testcases with

n,m,q≤1000 .

For each testcase, the first line contains three numbers

n,m,q (n,q≤105,m≤2×105) .

Then

m lines follow. Each line contains two numbers

ui,vi (1≤ui,vi≤105) which describe an edge of the graph.

Then

q lines follows. Each line contains two numbers

Li,Ri (1≤L≤R≤n) which describe an operation.

Output

For each operation you need print a single line with a single number - the answer of this operation.

Sample Input

Sample Output

2
1

Author

XJZX

Source

2015 Multi-University Training Contest 4

题意：

给定n个点m条边的无向图（有自环有重边） q个询问

对于某个询问 query : [l,r]

把所有的边形如 {u,v} u,v其中一个或者两个都不在区间[l,r]上的都删除，求此时残余图的连通分量数。

每个询问都是互相独立的，也就是每个询问都是从原图删除而来。

思路：

感觉很有道理的样子，写了一发，卡常数卡死人了。。

#pragma comment(linker, "/STACK:1024000000")
#include <iostream>
#include <fstream>
#include <string>
#include <time.h>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <stack>
#include <cstring>
#include <cmath>
#include <set>
#include <vector>
using namespace std;
template <class T>
inline bool rd(T &ret) {
char c; int sgn;
if (c = getchar(), c == EOF) return 0;
while (c != '-' && (c<'0' || c>'9')) c = getchar();
sgn = (c == '-') ? -1 : 1;
ret = (c == '-') ? 0 : (c - '0');
while (c = getchar(), c >= '0'&&c <= '9') ret = ret * 10 + (c - '0');
ret *= sgn;
return 1;
}
template <class T>
inline void pt(T x) {
if (x < 0) {
putchar('-');
x = -x;
}
if (x > 9) pt(x / 10);
putchar(x % 10 + '0');
}
typedef long long ll;
typedef pair<int, int> pii;
const int N = 1e5 + 100;
const int inf = 10000000;
struct BIT {
int c[N], maxn;
void init(int n) {
maxn = n;
memset(c, 0, (10 + n) *sizeof(int));
}
int lowbit(int x) { return x&-x; }
int sum(int x) {
int ans = 0;
while (x)ans += c[x], x -= lowbit(x);
return ans;
}
int query(int l, int r) {
return sum(r) - sum(l - 1);
}
void change(int x, int val) {
while (x<=maxn)c[x] += val, x += lowbit(x);
}
}bit;
struct Node *null;
struct Node {
Node *fa, *ch[2];
int val;
int mi, min_id, id;
bool rev;
inline void put() {
printf("%d: fa:%d [%d,%d] val:%d ma:%d,%d rev:%dn", id, fa->id, ch[0]->id, ch[1]->id, val, mi, min_id, rev);
}
inline void clear(int _id) {
fa = ch[0] = ch[1] = null;
rev = 0;
id = _id;
mi = inf;
min_id = 0;
val = 0;
}
inline void push_up() {
if (this == null)return;
if (val) {
mi = min(id, min(ch[0]->mi, ch[1]->mi));
if (id <= min(ch[0]->mi, ch[1]->mi)) min_id = id;
else if (ch[0]->mi < min(ch[1]->mi, id	))min_id = ch[0]->min_id;
else min_id = ch[1]->min_id;
}
else
{
mi = min(ch[0]->mi, ch[1]->mi);
if (ch[0]->mi < ch[1]->mi)min_id = ch[0]->min_id;
else min_id = ch[1]->min_id;
}
}
inline void push_down() {
if (this == null)return;
if (rev) {
ch[0]->flip();
ch[1]->flip();
rev = 0;
}
}
inline void setc(Node *p, int d) {
ch[d] = p;
p->fa = this;
}
inline bool d() {
return fa->ch[1] == this;
}
inline bool isroot() {
return fa == null || fa->ch[0] != this && fa->ch[1] != this;
}
inline void flip() {
if (this == null)return;
swap(ch[0], ch[1]);
rev ^= 1;
}
inline void go() {//从链头开始更新到this
if (!isroot())fa->go();
push_down();
}
inline void rot() {
Node *f = fa, *ff = fa->fa;
int c = d(), cc = fa->d();
f->setc(ch[!c], c);
this->setc(f, !c);
if (ff->ch[cc] == f)ff->setc(this, cc);
else this->fa = ff;
f->push_up();
}
inline Node*splay() {
go();
while (!isroot()) {
if (!fa->isroot())
d() == fa->d() ? fa->rot() : rot();
rot();
}
push_up();
return this;
}
inline Node* access() {//access后this就是到根的一条splay，并且this已经是这个splay的根了
for (Node *p = this, *q = null; p != null; q = p, p = p->fa) {
p->splay()->setc(q, 1);
p->push_up();
}
return splay();
}
inline Node* find_root() {
Node *x;
for (x = access(); x->push_down(), x->ch[0] != null; x = x->ch[0]);
return x;
}
void make_root() {
access()->flip();
}
void cut() {//把这个点的子树脱离出去
access();
ch[0]->fa = null;
ch[0] = null;
push_up();
}
void cut(Node *x) {
if (this == x || find_root() != x->find_root())return;
else {
x->make_root();
cut();
}
}
void link(Node *x) {
if (find_root() == x->find_root())return;
else {
make_root(); fa = x;
}
}
};
Node pool[N], *tail;
Node *node[N];
void init(int n) {
tail = pool;
null = tail++;
null->clear(0);
for (int i = 1; i <= n; i++) {
node[i] = tail++;
node[i]->clear(i);
}
}
void debug(Node *x) {
if (x == null)return;
x->put();
debug(x->ch[0]);
debug(x->ch[1]);
}
int n, m, q;
struct BST {
int f[N];
void init(int n) { for (int i = 1; i <= n; i++)f[i] = i; }
int find(int x) { return x == f[x] ? x : f[x] = find(f[x]); }
void Union(int u, int v) {
u = find(u); v = find(v);
if (u == v)return;
if (u > v)swap(u, v);
f[u] = v;
}
}cha;
void insert(int x, int y) {
//	puts("**===");	for (int i = 1; i <= max(x, y); i++)debug(node[i]), puts("");puts("");
if (cha.find(x) == cha.find(y)) {
node[y]->access();
//
puts("**");	for (int i = 1; i <= max(x, y); i++)debug(node[i]), puts("");puts("");
int id = node[y]->min_id;
if (y <= id)return;
//
printf("change id:%dn", id);
bit.change(id, -1);
node[id]->val--;
node[id]->cut(node[x]);
}
else cha.Union(x, y);
//	puts("---------");for (int i = 1; i <= x; i++)debug(node[i]), puts("");puts("");
bit.change(y, 1);
node[y]->make_root();
node[y]->val++;
node[y]->push_up();
node[y]->fa = node[x];
//	puts("@@@@@@");for (int i = 1; i <= x; i++)debug(node[i]), puts("");puts("");
}
int ans[N];
struct {
struct Edge {
int to, nex, id;
}edge[N << 1];
int head[N], edgenum;
void init(int n) {
memset(head, -1, (10 + n) *sizeof(int));
edgenum = 0;
}
void add(int u, int v, int id = 0) {
Edge E = { v, head[u], id};
edge[edgenum] = E;
head[u] = edgenum++;
}
}E, Q;
int main() {
while (~scanf("%d%d%d", &n,&m,&q)) {
E.init(n); Q.init(n); cha.init(n);
for (int i = 0, u, v;i < m; i++)
{
rd(u), rd(v);
if (u == v) {i--, m--;continue;}
if (u < v)E.add(v, u);else E.add(u, v);
}
for (int i = 0, u, v;i < q; i++) {
rd(u); rd(v);
Q.add(v, u, i);
}
bit.init(n);
init(n);
for (int i = 1; i <= n; i++)
{
for (int j = E.head[i]; ~j; j = E.edge[j].nex)
insert(i, E.edge[j].to);
for (int j = Q.head[i]; ~j; j = Q.edge[j].nex)
ans[Q.edge[j].id] = n - bit.query(Q.edge[j].to, i);
}
for (int i = 0; i < q; i++)	pt(ans[i]), puts("");
}
return 0;
}
/*
7 9 1
1 2
1 3
1 5
1 6
4 7
4 6
2 7
6 2
4 3
2 7
ans:3
*/