bzoj2049 线段树 + 可撤销并查集

#include <map>
#include <set>
#include <ctime>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
#define For(i, x, y) for(int i=x;i<=y;i++)  
#define _For(i, x, y) for(int i=x;i>=y;i--)
#define Mem(f, x) memset(f,x,sizeof(f))  
#define Sca(x) scanf("%d", &x)
#define Sca2(x,y) scanf("%d%d",&x,&y)
#define Sca3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define Scl(x) scanf("%lld",&x);  
#define Pri(x) printf("%d\n", x)
#define Prl(x) printf("%lld\n",x);  
#define CLR(u) for(int i=0;i<=N;i++)u[i].clear();
#define LL long long
#define ULL unsigned long long  
#define mp make_pair
#define PII pair<int,int>
#define PIL pair<int,long long>
#define PLL pair<long long,long long>
#define pb push_back
#define fi first
#define se second 
typedef vector<int> VI;
int read(){int x = 0,f = 1;char c = getchar();while (c<‘0‘ || c>‘9‘){if (c == ‘-‘) f = -1;c = getchar();}
while (c >= ‘0‘&&c <= ‘9‘){x = x * 10 + c - ‘0‘;c = getchar();}return x*f;}
const double eps = 1e-9;
const int maxn = 1e5 + 10;
const int maxm = 2e6 + 10;
const int INF = 0x3f3f3f3f;
const int mod = 1e9 + 7; 
int N,M,K;
struct Query{
    int t,u,v;
    Query(){}
    Query(int t,int u,int v):t(t),u(u),v(v){}
}q[maxm];
struct Line{
    int op,u,v;
    Line(){}
    Line(int op,int u,int v):op(op),u(u),v(v){}
}line[maxm];
map<PII,int>Q;
int Stack[maxm],top;
int size[maxn],fa[maxn];
void init(){
    for(int i = 0; i <= N ; i ++){
        fa[i] = -1; size[i] = 0;
    }
    top = 0;
}
//segment_tree
struct Tree{
    int l,r;
    int head;
}tree[maxm << 2];
struct Edge{
    PII data;
    int next;
}edge[maxm << 2];
int tot,cnt,cnt2;
void add(int u,PII v){
    edge[tot].next = tree[u].head;
    edge[tot].data = v;
    tree[u].head = tot++;
}
void Build(int t,int l,int r){
    tree[t].l = l; tree[t].r = r;
    tree[t].head = -1;
    if(l == r) return;
    int m = (l + r) >> 1;
    Build(t << 1,l,m); Build(t << 1 | 1,m + 1,r);
}
void update(int t,int l,int r,PII v){
    if(l <= tree[t].l && tree[t].r <= r){
        add(t,v);
        return;
    }
    int m = (tree[t].l + tree[t].r) >> 1;
    if(r <= m) update(t << 1,l,r,v);
    else if(l > m) update(t << 1 | 1,l,r,v);
    else{
        update(t << 1,l,m,v);
        update(t << 1 | 1,m + 1,r,v);
    }
}
int find(int x){
    while(fa[x] != -1) x = fa[x];
    return x;
}
void Union(int x,int y){
    x = find(x); y = find(y);
    if(x == y) return;
    if(size[x] > size[y]) swap(x,y);
    Stack[top++] = x;
    fa[x] = y;
    size[y] += size[x] + 1;
}
void rewind(int t){
    while(top > t){
        int x = Stack[--top];
        size[fa[x]] -= size[x] + 1;
        fa[x] = -1;
    }
}
void dfs(int t){
    int now = top;
    for(int i = tree[t].head; ~i; i = edge[i].next){
        PII v = edge[i].data;
        Union(v.fi,v.se);
    }
    if(tree[t].l == tree[t].r){
        while(tot <= cnt2 && q[tot].t == tree[t].l){
            if(find(q[tot].u) == find(q[tot].v)){
                puts("Yes");
            }else{
                puts("No");
            }
            tot++;
        }
        rewind(now);
        return;
    }
    dfs(t << 1); dfs(t << 1 | 1);
    rewind(now);
}
int main(){
    Sca2(N,M); init();
    cnt = 0,cnt2 = 0;
    for(int i = 1; i <= M ; i ++){
        char op[10]; int u,v;
        scanf("%s%d%d",op,&u,&v);
        if(u > v) swap(u,v);
        if(op[0] == ‘Q‘) q[++cnt2] = Query(cnt,u,v);
        else if(op[0] == ‘C‘) line[++cnt] = Line(0,u,v);
        else line[++cnt] = Line(1,u,v);
    }
    tot = 0; Build(1,0,cnt);
    for(int i = 1; i <= cnt; i ++){
        int &x = Q[mp(line[i].u,line[i].v)];
        if(line[i].op == 0) x = i;
        else{
            update(1,x,i - 1,mp(line[i].u,line[i].v));
            x = 0;
        }
    }
    for(map<PII,int>::iterator it = Q.begin(); it != Q.end(); it++){
        pair<PII,int> u = *it;
        if(u.se) update(1,u.se,cnt,u.fi);
    }
    tot = 1;
    dfs(1);
    return 0;
}