Treap 的合并
首先感谢 @Capella 的DeBug
其次,这是由一个 & 号引发的血案
注意对于所有修改操作都要 &
Treap的合并, 启发式合并,对于每一个节点都 insert ,注意垃圾回收
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#define ll long long
#define inf 0x3f3f3f3f
using namespace std;
const int MAXN = 500005;
int init() {
int rv = 0, fh = 1;
char c = getchar();
while(c < '0' || c > '9') {
if(c == '-') fh = -1;
c = getchar();
}
while(c >= '0' && c <= '9') {
rv = (rv<<1) + (rv<<3) + c - '0';
c = getchar();
}
return fh * rv;
}
int pool[MAXN], top, n, m, id[MAXN], q;
struct UFS {
int fa[MAXN];
void unit() {
for(int i = 1; i <= n; i++) fa[i] = i;
}
int find(int x) {
if(x != fa[x]) return fa[x] = find(fa[x]);
return fa[x];
}
}ufs;
struct node{
int val, dat, num, size, l, r;
}a[MAXN];
struct Treap{
int New(int x, int num) {
int ret = pool[++top];
a[ret].val = x;
a[ret].num = num;
a[ret].dat = rand();
a[ret].size = 1;
a[ret].l = a[ret].r = 0;
return ret;
}
void del(int &rt) {pool[top--] = rt;rt = 0;}
void PushUp(int rt) {
a[rt].size = a[a[rt].l].size + a[a[rt].r].size + 1;
}
void zig(int &rt) {
int nxt = a[rt].l;
a[rt].l = a[nxt].r; a[nxt].r = rt; rt = nxt;
PushUp(a[rt].r);
PushUp(rt);
}
void zag(int &rt) {
int nxt = a[rt].r;
a[rt].r = a[nxt].l; a[nxt].l = rt; rt = nxt;
PushUp(a[rt].l);
PushUp(rt);
}
void Insert(int &rt, int x, int num) {
if(!rt) {
rt = New(x, num);
return;
}
if(x < a[rt].val) {
Insert(a[rt].l, x, num);
if(a[a[rt].l].dat > a[rt].dat) zig(rt);
}else {
Insert(a[rt].r, x, num);
if(a[a[rt].r].dat > a[rt].dat) zag(rt);
}
PushUp(rt);
}
int GetNum(int rt, int x) {
if(!rt) return -1;
if(a[a[rt].l].size >= x) return GetNum(a[rt].l, x);
if(a[a[rt].l].size + 1 >=x) return a[rt].num;
return GetNum(a[rt].r,x - 1 - a[a[rt].l].size);
}
void merge(int /*x*/&x, int &y) {
if(!y) return;
if(a[y].l)
merge(x, a[y].l);
if(a[y].r)
merge(x, a[y].r);
Insert(x, a[y].val, a[y].num);del(y);
}
}bst;
void merge(int u, int v) {
int r1 = ufs.find(u), r2 = ufs.find(v);
if(r1 != r2) {
if(a[id[r1]].size < a[id[r2]].size) {
ufs.fa[r1] = r2;
bst.merge(id[r2], id[r1]);
}else {
ufs.fa[r2] = r1;
bst.merge(id[r1], id[r2]);
}
}
}
int main() {
n = init(); m = init();
ufs.unit();
for(int i = 0; i < MAXN; i++) pool[i] = i;
for(int i = 1; i <= n; i++) {
int t = init();
id[i] = bst.New(t, i);
}
for(int i = 1; i <= m; i++) {
int u = init(), v = init();
if(!u || !v) continue;
merge(u, v);
}
q = init();
for(int i = 1; i <= q; i++) {
char t;
scanf(" %c ", &t);
if(t == 'Q') {
int x = init(), k = init();
printf("%d\n", bst.GetNum(id[ufs.find(x)], k));
}else {
int u = init(), v = init();
if(!u || !v) continue;
merge(u, v);
}
}
return 0;
}