Submission #568760

#	Time	Username	Problem	Language	Result	Execution time	Memory
568760		ngpin04	Election (BOI18_election)	C++17	100 / 100	586 ms	57196 KiB

election

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define TASK ""
#define bit(x) (1LL << (x))
#define getbit(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end() 
using namespace std;
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) {
	return l + rd() % (r - l + 1);
}
const int N = 5e5 + 5; 
const int oo = 1e9;
const long long ooo = 1e18;
const int mod = 1e9 + 7; // 998244353;
const long double pi = acos(-1);

struct segtree {
	struct node {
		int sum, minr;

		node(int _sum = 0, int _minr = 0) {
			sum = _sum;
			minr = _minr;
		}	

		node operator + (const node &p) const {
			node res;
			res.sum = sum + p.sum;
			res.minr = min(p.minr, minr + p.sum);
			return res;
		}
	};

	int n;
	vector <node> st;

	segtree(int _n = 0) {
		n = _n;
		st.assign(4 * n + 5, node());
	}

	void update(int id, int l, int r, int pos, int val) {
		if (l > pos || r < pos)
			return;
		if (l == r) {
			st[id] = node(val, val);
			return;
		}
		int mid = (l + r) >> 1;
		update(id << 1, l, mid, pos, val);
		update(id << 1 | 1, mid + 1, r, pos, val);
		st[id] = st[id << 1] + st[id << 1 | 1];
	}

	void update(int pos, int val) {
		update(1, 1, n, pos, val);
	}

	node getval(int id, int l, int r, int u, int v) {
		if (l > v || r < u)
			return node();
		if (l >= u && r <= v)
			return st[id];
		int mid = (l + r) >> 1;
		node lnode = getval(id << 1, l, mid, u, v);
		node rnode = getval(id << 1 | 1, mid + 1, r, u, v);
		return lnode + rnode;
	}

	int getval(int l, int r) {
		return getval(1, 1, n, l, r).minr;
	}
};

vector <int> qr[N];

int ans[N];
int bit[N];
int l[N];
int r[N];
int a[N];
int n, q;

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	#ifdef ONLINE_JUDGE
	// freopen(TASK".inp","r",stdin);
	// freopen(TASK".out","w",stdout);
	#endif
	cin >> n;
	{
		string s; cin >> s;
		for (int i = 1; i <= n; i++)
			a[i] = (s[i - 1] == 'C') ? 1 : -1;
	}
	cin >> q;
	for (int i = 1; i <= q; i++) {
		cin >> l[i] >> r[i];
		qr[l[i]].push_back(i);
	}

	segtree st(n);

	vector <int> pos;
	for (int i = n; i >= 1; i--) {
		if (a[i] < 0)
			pos.push_back(-i);	
		else {
			if (pos.size()) {
				st.update(-pos.back(), -1);
				pos.pop_back();
			}
			st.update(i, 1);
		} 	

		for (int ind : qr[i]) {
			int cntdel = (int) pos.size() - 
			(lower_bound(ALL(pos), -r[ind]) - pos.begin());
			ans[ind] = max(0, -st.getval(l[ind], r[ind])) + cntdel;
		}
	}

	for (int i = 1; i <= q; i++)
		cout << ans[i] << "\n";
	return 0;
}

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