https://scut.online/p/278
第一次遇到不需要并查集的左偏树。
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int n,m;
const int MAXN=1000005;
int tot,v[MAXN],l[MAXN],r[MAXN],d[MAXN];
int gc[MAXN]; //gc[i]表示编号为i的工厂所在的左偏树是哪个x
class Leftist_Tree {
inline int _Merge(int x,int y) {
if(!x||!y)
return x+y;
//<就是大顶堆
if(v[x]<v[y])
swap(x,y);
r[x]=_Merge(r[x],y);
if(d[l[x]]<d[r[x]])
swap(l[x],r[x]);
d[x]=d[r[x]]+1;
return x;
}
inline int Build(int val=-1) {
tot++;
l[tot]=r[tot]=d[tot]=0;
v[tot]=val;
return tot;
}
public:
inline void Init() {
tot=0;
v[0]=-1;
//memset(gc,0,sizeof(gc));多组数据时要把工厂指回空树
}
inline void Push(int &x,int &val) {
//向x工厂加入节点val
int rt=Build(val);
gc[x]=_Merge(rt,gc[x]);
}
inline int Pop(int &x) {
//把x工厂的顶端弹出,没有顶端弹出v[0],那个节点还在只不过失联了而已
int gcx=gc[x];
gc[x]=_Merge(l[gcx],r[gcx]);
return v[gcx];
}
inline void Merge(int &x,int &y) {
//把y工厂合并到x工厂
gc[x]=_Merge(gc[x],gc[y]);
gc[y]=Build();
}
} lt;
inline int read() {
int x=0;
char c;
do {
c=getchar();
} while(c<'0'||c>'9');
do {
x=(x<<3)+(x<<1)+c-'0';
c=getchar();
} while(c>='0'&&c<='9');
return x;
}
inline void _write(int x) {
if(x>9)
_write(x/10);
putchar(x%10+'0');
}
inline void write(int x) {
if(x<0) {
putchar('-');
x=-x;
}
_write(x);
putchar('\n');
}
int main() {
#ifdef Yinku
freopen("Yinku.in","r",stdin);
#endif // Yinku
int n=read(),m=read();
lt.Init();
for(int i=1; i<=m; i++) {
int ins=read();
switch(ins) {
case 1: {
int x=read(),v=read();
lt.Push(x,v);
break;
}
case 2: {
int x=read(),y=read();
lt.Merge(x,y);
break;
}
case 3: {
int x=read();
//printf("%d\n",lt.Pop(x));
write(lt.Pop(x));
break;
}
}
}
}