Submission #508480

#	Time	Username	Problem	Language	Result	Execution time	Memory
508480		stefantaga	Election (BOI18_election)	C++14	100 / 100	523 ms	27796 KiB

election

#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

struct Node {
	int l_max, r_max, tot, ans;

	Node operator+(Node b) {
		Node ret;
		ret.l_max = max(l_max, b.l_max + tot);
		ret.r_max = max(r_max + b.tot, b.r_max);
		ret.tot = tot + b.tot;
		ret.ans = max(max(ans + b.tot, b.ans + tot), l_max + b.r_max);
		return ret;
	}
};

Node segtree[2000001];
char s[500001];
int n;

void build(int node = 1, int l = 1, int r = n) {
	if (l == r) {
		if (s[l] == 'T') segtree[node] = {1, 1, 1, 1};
		else segtree[node] = {0, 0, -1, 0};
	} else {
		int mid = (l + r) / 2;
		build(node * 2, l, mid);
		build(node * 2 + 1, mid + 1, r);
		segtree[node] = segtree[node * 2] + segtree[node * 2 + 1];
	}
}

Node query(int a, int b, int node = 1, int l = 1, int r = n) {
	if (l > b || r < a) return {0, 0, 0, 0};
	if (l >= a && r <= b) return segtree[node];
	int mid = (l + r) / 2;
	return query(a, b, node * 2, l, mid) + query(a, b, node * 2 + 1, mid + 1, r);
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	FOR(i, 1, n + 1) cin >> s[i];
	build();
	int q;
	cin >> q;
	while (q--) {
		int a, b;
		cin >> a >> b;
		cout << query(a, b).ans << '\n';
	}
	return 0;
}

• Subtask 1: 28 / 28
• Subtask 2: 54 / 54
• Subtask 3: 18 / 18