Submission #882949

#	Time	Username	Problem	Language	Result	Execution time	Memory
882949		tsumondai	Real Mountains (CCO23_day1problem2)	C++14	25 / 25	3619 ms	279816 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define foru(i, l, r) for(int i = l; i <= r; i++)
#define ford(i, r, l) for(int i = r; i >= l; i--)
#define __TIME  (1.0 * clock() / CLOCKS_PER_SEC)

typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;

const int N = 1e6 + 5;

const int oo = 1e18, mod = 1e6 + 3;

int n, m, k, h[N];
map<int, vector<int>> add, del;
set<int> s;
int nodes[4*N];

void build(int id, int l, int r) {
	if (l == r) {
		nodes[id] = h[l];
		return;
	}

	int mid = (l + r) >> 1;

	build(id << 1, l, mid);
	build(id << 1 | 1, mid + 1, r);

	nodes[id] = min(nodes[id << 1], nodes[id << 1 | 1]);
}

void update(int id, int l, int r, int pos) {
	if (l == r) {
		nodes[id] = oo;
		return;
	}

	int mid = (l + r) >> 1;

	if (pos <= mid) update(id << 1, l, mid, pos);
	else update(id << 1 | 1, mid + 1, r, pos);

	nodes[id] = min(nodes[id << 1], nodes[id << 1 | 1]);
}

int get(int id, int l, int r, int u, int v) {
	if (u > r || v < l /*|| l>r || u>v*/) return oo;
	if (l >= u && r <= v) return nodes[id];
	int mid = (l + r) >> 1;
	return min(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}

int calc(int l, int r) {
	if (s.empty()) return 0;
	int res = 0;
	int x = *s.begin(), y = *s.rbegin();
	int lx = get(1, 1, n, 1, x), ry = get(1, 1, n, y, n);
	int sum = ((r - l) * (l + r - 1) / 2) % mod;
	if (x == y) return ((lx + ry) * (r - l) + sum) % mod;
	int add = lx + ry + r;
	res = (res + add * (r - l)) % mod;
	int sz = (int)s.size();
	res = ((res + (3 * sum + 2 * (r - l)) * (sz - 1) - (r - l)) % mod + mod) % mod;
	return res;
}

void process() {
	cin >> n;
	foru(i, 1, n) {
		cin >> h[i];
		add[h[i]].pb(i);
	}
	build(1, 1, n);
	int p = max_element(h + 1, h + n + 1) - h;
	foru(i, 1, p) h[i] = max(h[i], h[i - 1]);
	ford(i, n, p) h[i] = max(h[i], h[i + 1]);
	foru(i, 1, n) del[h[i]].push_back(i);
	int pre = -1, ans = 0;
	for (auto &it : add) {
		if (pre != -1) ans = (ans + calc(pre, it.fi)) % mod;
		for (int x : it.se) {
			s.insert(x);
			update(1, 1, n, x);
		}
		for (int x : del[it.fi]) s.erase(x);
		pre = it.fi;
	}
	cout << ans << '\n';
	return;
}

signed main() {
	cin.tie(0)->sync_with_stdio(false);
	//freopen(".inp", "r", stdin);
	//freopen(".out", "w", stdout);
	process();
	cerr << "Time elapsed: " << __TIME << " s.\n";
	return 0;
}

/*
Xét các trường hợp đặc biệt
Kiểm tra lại input/output
Cố gắng trâu
Lật ngược bài toán
Keep calm and get VOI
Flow:

*/

• Subtask 1: 3 / 3
• Subtask 2: 3 / 3
• Subtask 3: 3 / 3
• Subtask 4: 3 / 3
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 4 / 4