Monkey King HDU - 1512 （左偏树）

 1 //左偏树
 2 #include <bits/stdc++.h>
 3 using namespace std;
 4 const int maxn = 100010;
 5 struct Node{
 6     int val, dis, l, r;
 7 }p[maxn];
 8 int f[maxn];
 9 int gf(int x){
10     return x == f[x] ? f[x] : f[x] = gf(f[x]);
11 }
12 inline void maintain(int rt){
13     f[p[rt].r] = rt;  
14 }
15 int merge(int x, int y){
16     if(!x) return y;
17     if(!y) return x;
18     if(p[x].val < p[y].val) swap(x, y);
19     p[x].r = merge(p[x].r, y);
20     maintain(x);   // 维护右子树的父亲
21     int l = p[x].l, r = p[x].r;
22     if(p[l].dis < p[r].dis) swap(p[x].l, p[x].r);
23     if(p[x].r == 0) p[x].dis = 0;
24     else p[x].dis = p[p[x].r].dis + 1;
25     return x;
26 } 
27 int pop(int x){
28     int l = p[x].l, r = p[x].r;
29     p[x].dis = 0;
30     p[x].l = p[x].r = 0;
31     f[l] = l; f[r] = r;   //维护父亲
32     return merge(l, r);
33 }
34 int main(){
35     int n, m;
36     while(scanf("%d", &n) != EOF){
37         for(int i = 1; i <= n; i++){
38             scanf("%d", &p[i].val);
39             p[i].l = p[i].r = p[i].dis = 0;
40             f[i] = i;
41         }
42         scanf("%d", &m);
43         while(m--){
44             int a, b;
45             scanf("%d %d", &a, &b);
46             int pa = gf(a), pb = gf(b);
47             if(pa == pb) puts("-1");
48             else{
49                 p[pa].val /= 2;
50                 p[pb].val /= 2;
51                 int l = pop(pa), r = pop(pb);
52                 l = merge(l, pa);
53                 r = merge(r, pb);
54                 l = merge(l, r);
55                 printf("%d\n", p[l].val);
56             }
57         }
58     }
59     return 0;
60 }