[BZOJ1588][HNOI2002]营业额统计

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
#include <cmath>
using namespace std;

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

#define maxn 50010
#define oo 2147483647
struct Node {
	int v, r, minv, maxv;
	Node() {}
	Node(int _, int __): v(_), r(__) {}
} ns[maxn];
int ToT, rt, ch[2][maxn], fa[maxn];

void maintain(int o) {
	ns[o].minv = ns[o].maxv = ns[o].v;
	for(int i = 0; i < 2; i++) if(ch[i][o])
		ns[o].minv = min(ns[o].minv, ns[ch[i][o]].minv), ns[o].maxv = max(ns[o].maxv, ns[ch[i][o]].maxv);
	return ;
}
void rotate(int u) {
	int y = fa[u], z = fa[y], l = 0, r = 1;
	if(z) ch[ch[1][z]==y][z] = u;
	if(ch[1][y] == u) swap(l, r);
	fa[u] = z; fa[y] = u; fa[ch[r][u]] = y;
	ch[l][y] = ch[r][u]; ch[r][u] = y;
	maintain(y); maintain(u);
	return ;
}
void insert(int& o, int v) {
	if(!o) {
		ns[o = ++ToT] = Node(v, rand());
		return maintain(o);
	}
	bool d = v > ns[o].v;
	insert(ch[d][o], v); fa[ch[d][o]] = o;
	if(ns[ch[d][o]].r > ns[o].r) {
		int t = ch[d][o];
		rotate(t); o = t;
	}
	return maintain(o);
}
int fans;
void Find(int o, int v) {
	if(!o) return ;
	if(ns[o].v == v){ fans = 0; return ; }
	fans = min(fans, abs(v - ns[o].v));
	for(int i = 0; i < 2; i++) if(ch[i][o])
		fans = min(fans, min(abs(v - ns[ch[i][o]].minv), abs(v - ns[ch[i][o]].maxv)));
	bool d = v > ns[o].v;
	Find(ch[d][o], v);
	return ;
}

int main() {
	int q = read(), ans = read();
	insert(rt, ans); q--;
	while(q--) {
		int v = read();
		fans = oo; Find(rt, v);
		ans += fans;
//		printf("get: %d\n", fans);
		insert(rt, v);
	}
	printf("%d\n", ans);
	
	return 0;
}