127 lines
2.9 KiB
C++
127 lines
2.9 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 201000;
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// Splay树，没有仔细研究
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// 区间第k大就必须得splay了
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struct splay_tree {
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int ff, cnt, ch[2], val, size;
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} t[N];
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int root, tot;
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void update(int x) {
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t[x].size = t[t[x].ch[0]].size + t[t[x].ch[1]].size + t[x].cnt;
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}
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void rotate(int x) {
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int y = t[x].ff;
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int z = t[y].ff;
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int k = (t[y].ch[1] == x);
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t[z].ch[(t[z].ch[1] == y)] = x;
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t[x].ff = z;
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t[y].ch[k] = t[x].ch[k ^ 1];
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t[t[x].ch[k ^ 1]].ff = y;
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t[x].ch[k ^ 1] = y;
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t[y].ff = x;
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update(y);
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update(x);
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}
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void splay(int x, int s) {
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while (t[x].ff != s) {
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int y = t[x].ff, z = t[y].ff;
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if (z != s)
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(t[z].ch[0] == y) ^ (t[y].ch[0] == x) ? rotate(x) : rotate(y);
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rotate(x);
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}
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if (s == 0)
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root = x;
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}
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void find(int x) {
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int u = root;
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if (!u)
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return;
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while (t[u].ch[x > t[u].val] && x != t[u].val)
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u = t[u].ch[x > t[u].val];
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splay(u, 0);
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}
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void insert(int x) {
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int u = root, ff = 0;
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while (u && t[u].val != x) {
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ff = u;
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u = t[u].ch[x > t[u].val];
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}
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if (u)
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t[u].cnt++;
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else {
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u = ++tot;
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if (ff)
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t[ff].ch[x > t[ff].val] = u;
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t[u].ch[0] = t[u].ch[1] = 0;
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t[tot].ff = ff;
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t[tot].val = x;
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t[tot].cnt = 1;
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t[tot].size = 1;
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}
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splay(u, 0);
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}
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int Next(int x, int f) {
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find(x);
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int u = root;
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if (t[u].val > x && f)
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return u;
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if (t[u].val < x && !f)
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return u;
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u = t[u].ch[f];
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while (t[u].ch[f ^ 1])
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u = t[u].ch[f ^ 1];
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return u;
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}
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void Delete(int x) {
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int last = Next(x, 0);
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int Net = Next(x, 1);
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splay(last, 0);
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splay(Net, last);
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int del = t[Net].ch[0];
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if (t[del].cnt > 1) {
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t[del].cnt--;
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splay(del, 0);
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} else
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t[Net].ch[0] = 0;
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}
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int kth(int x) {
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int u = root;
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while (t[u].size < x)
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return 0;
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while (1) {
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int y = t[u].ch[0];
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if (x > t[y].size + t[u].cnt) {
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x -= t[y].size + t[u].cnt;
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u = t[u].ch[1];
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} else if (t[y].size >= x)
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u = y;
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else
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return t[u].val;
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}
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}
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int main() {
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int n;
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scanf("%d", &n);
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insert(1e9);
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insert(-1e9);
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while (n--) {
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int opt, x;
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scanf("%d%d", &opt, &x);
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if (opt == 1)
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insert(x);
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if (opt == 2)
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Delete(x);
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if (opt == 3) {
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find(x);
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printf("%d\n", t[t[root].ch[0]].size);
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}
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if (opt == 4)
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printf("%d\n", kth(x + 1));
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if (opt == 5)
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printf("%d\n", t[Next(x, 0)].val);
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if (opt == 6)
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printf("%d\n", t[Next(x, 1)].val);
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}
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return 0;
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} |