Luogu3871 [TJOI2010]中位数 （平衡树）

"#define int long long" 导致100pts \(\rightarrow\) 80pts

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long

#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);

#else

#define D_e_Line ;
#define D_e(x)  ;
#define Pause() ;
#define FileOpen() ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

const int N = 100007;

struct Treap{
    int ch[2], fa, val, siz, tot;
}t[N << 2];
int root, treeIndex;
inline void Pushup(int rt){
    t[rt].siz = t[t[rt].ch[0]].siz + t[t[rt].ch[1]].siz + t[rt].tot;
}
inline int Ident(int x){
    return t[t[x].fa].ch[1] == x;
}
inline void Rotate(int x){
    int y = t[x].fa, z = t[y].fa, k = Ident(x);
    t[z].ch[Ident(y)] = x, t[x].fa = z;
    t[y].ch[k] = t[x].ch[k ^ 1], t[t[x].ch[k ^ 1]].fa = y;
    t[x].ch[k ^ 1] = y, t[y].fa = x;
    Pushup(y), Pushup(x);
}
inline void Splay(int x, int pos){
    while(t[x].fa != pos){
        int y = t[x].fa, z = t[y].fa;
        if(z != pos){
            Ident(x) == Ident(y) ? Rotate(y) : Rotate(x);
        }
        Rotate(x);
    }
    if(!pos) root = x;
}
inline void Insert(int x){
    int u = root, fa = 0;
    while(u && t[u].val != x){
        fa = u;
        u = t[u].ch[x > t[u].val];
    }
    if(u){
        ++t[u].tot;
    }
    else{
        u = ++treeIndex;
        t[u].val = x;
        t[u].fa =fa;
        t[u].ch[0] = t[u].ch[1] = 0;
        t[u].siz = t[u].tot = 1;
        if(fa) t[fa].ch[x > t[fa].val] = u; // !
    }
    Splay(u, 0);
}
inline int Kth(int x){
    int u = root;
    if(t[u].siz < x) return 0;
    while(1){
        int v = t[u].ch[1];
        if(t[v].siz + t[u].tot < x){
            x -= t[v].siz + t[u].tot;
            u = t[u].ch[0]; // !
        }
        else if(t[v].siz >= x){
            u = v;
        }
        else{
            return t[u].val;
        }
    }
}
int main(){
    int n;
    io >> n;
    Insert(2147483647);
    Insert(-2147483647);
    R(i,1,n){
        int x;
        io >> x;
        Insert(x);
    }
    int m;
    io >> m;
    while(m--){
        char str[7];
        scanf("%s", str + 1);
        if(str[1] == 'a'){
            int x;
            io >> x;
            Insert(x);
            ++n;
        }
        else{
            if(n & 1){
                printf("%d\n", Kth(((n + 1) >> 1) + 1));
            }
            else{
                int ans1 = Kth((n >> 1) + 1);
                int ans2 = Kth(((n + 2) >> 1) + 1);
                printf("%d\n", Min(ans1, ans2));
            }
        }
    }
    
    return 0;
}

Luogu3871 [TJOI2010]中位数 （平衡树）

原文：https://www.cnblogs.com/bingoyes/p/11264303.html