(Updating)【区间操作数据结构例题】

#include<bits/stdc++.h>
#define lc tr[p].ch[0]
#define rc tr[p].ch[1]
using namespace std;
const int maxn = 2500005, inf=0x3f3f3f3f;

int read() {
    int o=0, f=1;
    char ch;
    while(!isdigit(ch=getchar())) if(ch==‘-‘) f=-1;
    while(isdigit(ch)) o=o*10+ch-‘0‘, ch=getchar();
    return o*f;
}

struct Treap{
    int ch[2];
    int val, cnt;
    int siz, rk;
} tr[maxn];

void up(int p) { tr[p].siz = tr[lc].siz + tr[rc].siz + 1; }

void rotate(int &p, int d) {
    int son = tr[p].ch[d];
    tr[p].ch[d] = tr[son].ch[d^1];
    tr[son].ch[d^1] = p;
    up(p); up(p=son);
}

int np=0;
void insert(int &p, int x) {
    if(!p) {
        tr[p=++np] = (Treap){0, 0, x, 1, 1, rand()};
        return;
    }
    tr[p].siz++;
    if(tr[p].val == x) { tr[p].cnt++; return; }
    int d = tr[p].val < x; insert(tr[p].ch[d], x);
    if(tr[p].rk > tr[tr[p].ch[d]].rk) rotate(p, d);
}

void del(int &p, int x) {
    if(!p) return;
    if(tr[p].val == x) {
        if(tr[p].cnt > 1) {
            tr[p].siz--;
            tr[p].cnt--;
            return;
        }
        if(!lc || !rc) {
            p = lc + rc; // 利用引用更新父节点指向 
            return;
        }
        int d = tr[rc].rk < tr[lc].rk;
        rotate(p, d);
        del(p, x);
    } else {
        int d = tr[p].val < x;
        del(tr[p].ch[d], x);
        up(p);
    }
}

int find(int p, int x) {
    while(p && tr[p].val != x)
        if(tr[p].val < x) p=rc;
        else p=lc;
    return p;
}

int Max(int p) {
    while(p && rc) p=rc;
    return p;
}

int Min(int p) {
    while(p && lc) p=lc;
    return p;
}

int pred(int p, int x) {
    if(!p) return -inf;
    if(tr[p].val >= x) return pred(lc, x);
    return max(tr[p].val, pred(rc, x));
}

int suc(int p, int x) {
    if(!p) return inf;
    if(tr[p].val <= x) return suc(rc, x);
    return min(tr[p].val, suc(lc, x));
}

void prt(int p) {
    if(!p) return;
    prt(lc);
    printf("%d %d %d %d %d\n", p, tr[p].val, tr[p].cnt, lc, rc);
    prt(rc);
}

int main() {
    int n=read(), m=read(), rt=0;
    while(n--) insert(rt, read());
    while(m--) {
        char op[10];
        scanf("%s", op);
        if(op[0] == ‘I‘) insert(rt, read());
        else if(op[0] == ‘D‘) del(rt, read());
        else if(op[0] == ‘F‘) puts( find(rt, read())? "Y" : "N");
        else if(op[0] == ‘P‘) {
            int t=pred(rt, read());
            if(t != -inf) printf("%d\n", t);
        }
        else if(op[0] == ‘S‘) {
            int t=suc(rt, read());
            if(t != inf) printf("%d\n", t);
        }
        else if(op[1] == ‘i‘) {
            if(rt) printf("%d\n", tr[Min(rt)].val);
        }
        else {
            if(rt) printf("%d\n", tr[Max(rt)].val);
        }
    }
    return 0;
}