無旋treap板子!
阿新 • • 發佈:2018-02-12
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#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <cstdlib>
#define space putchar(' ')
#define enter putchar('\n')
using namespace std;
typedef long long ll;
template <class T>
void read(T &x){
char c;
bool op = 0;
while(c = getchar(), c < '0' || c > '9')
if(c == '-') op = 1;
x = c - '0';
while(c = getchar(), c >= '0' && c <= '9')
x = x * 10 + c - '0';
if(op) x = -x;
}
template <class T>
void write(T x){
if(x < 0) putchar('-'), x = -x;
if(x >= 10) write(x / 10);
putchar('0' + x % 10);
}
const int N = 100005, INF = 0x3f3f3f3f;
typedef pair<int, int> par;
#define mp make_pair
int n, tot, root;
int ls[N], rs[N], data[N], key[N], sze[N];
void upt(int u){
sze[u] = sze[ls[u]] + sze[rs[u]] + 1 ;
}
par split(int u, int k){
if(!k) return mp(0, u);
int l = ls[u], r = rs[u];
if(k == sze[l]) return ls[u] = 0, upt(u), mp(l, u);
if(k == sze[l] + 1) return rs[u] = 0, upt(u), mp(u, r);
if(k < sze[l]){
par tmp = split(l, k);
return ls[u] = tmp.second, upt(u), mp(tmp.first, u);
}
par tmp = split(r, k - sze[ls[u]] - 1);
return rs[u] = tmp.first, upt(u), mp(u, tmp.second);
}
int merge(int u, int v){
if(u == 0 || v == 0) return u + v;
if(key[u] < key[v]) return rs[u] = merge(rs[u], v), upt(u), u;
else return ls[v] = merge(u, ls[v]), upt(v), v;
}
int getrank(int u, int x){
int cnt = 0, ans = INF;
while(u){
if(x == data[u]) ans = min(ans, cnt + sze[ls[u]] + 1);
if(x > data[u]) cnt += sze[ls[u]] + 1, u = rs[u];
else u = ls[u];
}
return ans == INF ? cnt : ans;
}
int getkth(int u, int k){
while(1){
if(k == sze[ls[u]] + 1) return data[u];
if(k <= sze[ls[u]]) u = ls[u];
else k -= sze[ls[u]] + 1, u = rs[u]; //先修改k再移動u!我居然又寫錯了
}
}
int getpre(int u, int x){
int ans = -INF;
while(u){
if(data[u] < x) ans = max(ans, data[u]), u = rs[u];
else u = ls[u];
}
return ans;
}
int getnxt(int u, int x){
int ans = INF;
while(u){
if(data[u] > x) ans = min(ans, data[u]), u = ls[u];
else u = rs[u];
}
return ans;
}
void insert(int x){
data[++tot] = x, key[tot] = rand(), sze[tot] = 1;
int k = getrank(root, x);
par tmp = split(root, k);
root = merge(tmp.first, tot);
root = merge(root, tmp.second);
}
void erase(int x){
int k = getrank(root, x);
par tmp1 = split(root, k);
par tmp2 = split(tmp1.first, k - 1);
root = merge(tmp2.first, tmp1.second);
}
int main(){
srand(20010424);
read(n);
int op, x;
while(n--){
read(op), read(x);
if(op == 1) insert(x);
else if(op == 2) erase(x);
else if(op == 3) write(getrank(root, x)), enter;
else if(op == 4) write(getkth(root, x)), enter;
else if(op == 5) write(getpre(root, x)), enter;
else write(getnxt(root, x)), enter;
}
return 0;
}
無旋treap板子!