Rt

Code:

#include <bits/stdc++.h>

using namespace std;

const int N = 200010;
typedef long long LL;

int c, m;
int hh = 1, tt = 0;

struct Node
{
	int l, r;
	LL sum; int maxv;
}tr[N * 4];

void build(int u, int l, int r)
{
	if (l == r) tr[u] = {l, r, 0, 0};
	else
	{
		tr[u] = {l, r};
		int mid = l + r >> 1;
		build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
	} 
}

void modify(int u, int x, LL v, int y)
{
	if (tr[u].l == tr[u].r) tr[u].sum += v, tr[u].maxv += y;
	else
	{
		int mid = tr[u].l + tr[u].r >> 1;
		if (x <= mid) modify(u << 1, x, v, y);
		else modify(u << 1 | 1, x, v, y);
		tr[u].sum = tr[u << 1].sum + tr[u << 1 | 1].sum;
		tr[u].maxv = max(tr[u << 1].maxv, tr[u << 1 | 1].maxv);
	}
}

int query_max(int u, int l, int r)
{
	if (l > r) return 0;
	if (tr[u].l >= l && tr[u].r <= r) return tr[u].maxv;
	int mid = tr[u].l + tr[u].r >> 1;
	int res = 0;
	if (l <= mid) res = max(res, query_max(u << 1, l, r));
	if (r > mid) res = max(res, query_max(u << 1 | 1, l, r));
	return res;
}

LL query_sum(int u, int l, int r)
{
	if (l > r) return 0;
	if (tr[u].l >= l && tr[u].r <= r) return tr[u].sum;
	int mid = tr[u].l + tr[u].r >> 1;
	LL res = 0;
	if (l <= mid) res += query_sum(u << 1, l, r);
	if (r > mid) res += query_sum(u << 1 | 1, l, r);
	return res;
}

int main()
{
//	freopen("queue.in", "r", stdin);
//	freopen("queue.out", "w", stdout);
	scanf("%d%d", &c, &m); build(1, 1, N - 1);
	for (int i = 1; i <= m; i ++ )
	{
		int op, x;
		scanf("%d", &op);
		if (op == 4) printf("%d\n", query_max(1, hh, tt));
		else
		{
			scanf("%d", &x);
			if (op == 1)
			{
				tt ++ ;
				modify(1, tt, x, x);
			}
			else if (op == 2)
			{
				int l = hh - 1, r = tt;
				while (l < r)
				{
					int mid = l + r >> 1;
					if (query_sum(1, hh, mid) <= x) l = mid + 1;
					else r = mid;
				}
				x -= query_sum(1, hh, l - 1);
				hh = l;
				modify(1, hh, -x, 0);
			}
			else
			{
				int l = hh - 1, r = tt;
				while (l < r)
				{
					int mid = l + r + 1 >> 1;
					if (query_sum(1, hh, mid) < x) l = mid;
					else r = mid - 1;
				}
				x -= query_sum(1, hh, l);
				printf("%lld\n", query_max(1, l + 1, l + 1) - query_sum(1, l + 1, l + 1) + x);
			}
		}
//		puts("The queue:");
//		for (int i = hh; i <= tt; i ++ ) 
//		{
//			printf("%d %d\n", query_max(1, i, i), query_sum(1, i, i));
//		}
//		puts("\n\n\n");
	}
	
	return 0;
}