营业额统计

题目描述

思路

代码

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#define min(a, b) ((a) < (b) ? a : b)

const int MAX = (1<<15) + 5;
int n, m, tot, rt, inf = 0x3f3f3f3f;
long long ans;
struct Node {
	int lc, rc, cnt, size, key, pri;
	#define lc(x) t[x].lc
	#define rc(x) t[x].rc
	#define cnt(x) t[x].cnt
	#define size(x) t[x].size
	#define key(x) t[x].key
	#define pri(x) t[x].pri
} t[MAX];

void update(int &r) { size(r) = size(lc(r)) + size(rc(r)) + cnt(r); }

void zig(int &r) {
	int s = lc(r);
	lc(r) = rc(s);
	rc(s) = r;
	size(s) = size(r);
	update(r);
	r = s;
}

void zag(int &r) {
	int s = rc(r);
	rc(r) = lc(s);
	lc(s) = r;
	size(s) = size(r);
	update(r);
	r = s;
}

void insert(int &r, int k) {
	if (!r) {
		r = ++tot;
		cnt(r) = size(r) = 1;
		pri(r) = rand(), key(r) = k;
		return;
	} else ++size(r);
	if (k == key(r)) ++cnt(r);
	else if(k < key(r)) {
		insert(lc(r), k);
		if (pri(lc(r)) < pri(r)) zig(r);
	} else {
		insert(rc(r), k);
		if (pri(rc(r)) < pri(r)) zag(r);
	}
}

void delt(int &r, int k) {
	if (k == key(r)) {
		if (cnt(r) >= 2) cnt(r)--, size(r)--;
		else if (!lc(r) || !rc(r)) r = lc(r) + rc(r);
		else if (pri(lc(r)) < pri(r)) zag(r), delt(r, k);
		else zig(r), delt(r, k);
		return;
	}
	if (k < key(r)) delt(lc(r), k);
	else delt(rc(r), k);
}

int queryPre(int k) {
	int r = rt, res = inf;
	while (r) {
		if (key(r) <= k) res = key(r), r = rc(r);
		else r = lc(r);
	}
	return res;
}

int queryNxt(int k) {
	int r = rt, res = inf;
	while (r) {
		if (key(r) > k) res = key(r), r = lc(r);
		else r = rc(r);
	}
	return res;
}

int queryKth(int k) {
	int r = rt, res = inf;
	while (r) {
		if (size(lc(r)) < k && size(lc(r)) + cnt(r) >= k) return  key(r);
		else if (size(lc(r)) >= k) r = lc(r);
		else k -= size(lc(r)) + cnt(r), r = rc(r); 
	}
	return res;
}

int queryRand(int k) {
	int r = rt, res = 0;
	while (r) {
		if (k == key(r)) return size(lc(r)) + cnt(r) + 1;
		else if (k < key(r)) r = lc(r);
		else res += size(lc(r)) + cnt(r), r = rc(r);
	}
	return res;
}

inline int read() {
	int s = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9') {
		if (ch == '-') f = -1;
		ch = getchar();
	}
	while (ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar();
	return s * f;
}
void write(long long x) {
	if (x > 9) write(x / 10);
	putchar(x % 10 + '0');
}
int main() {
	srand(time(NULL));
	n = read(), m = read();
	ans = m;
	insert(rt, m);
	for (int i = 2, j; i <= n; ++i) {
		j = read();
		int a = queryPre(j), b = queryNxt(j);
		// printf("pre:%d nxt:%d ", a, b);
		ans += min(abs(j - a), b - j);
		// printf("ans: %d
", ans);
		insert(rt, j);
	}
	write(ans);
	return 0;
}