Submission #167738

#	Time	Username	Problem	Language	Result	Execution time	Memory
167738		qkxwsm	Street Lamps (APIO19_street_lamps)	C++14	100 / 100	3186 ms	403680 KiB

street_lamps

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

template<class T, class U>
void ckmin(T &a, U b)
{
	if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
	if (a < b) a = b;
}

struct custom_hash
{
	template<class T>
	T operator()(T v) const
	{
		return (v ^ (v >> 27)) * 2696969696969696969ll;
	}
};

template<class T, class U> using hash_table = gp_hash_table<T, U, custom_hash>;

#define y1 orz
#define y2 tmw
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()
#define MAXN 351313
#define INF 1000000007

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

int N, Q;
bitset<MAXN> state;
pii quer[MAXN];
hash_table<int, ll> fen[MAXN];
int lst[MAXN];
set<int> lts, rts;
int ans;

void upd(int x, int y, int val)
{
	for (int e = x + 1; e <= N; e += e & (-e))
	{
		for (int f = y + 1; f <= N; f += f & (-f))
		{
			fen[e][f] += val;
		}
	}
}
ll qry(int x, int y)
{
	ll res = 0;
	for (int e = x + 1; e; e -= e & (-e))
	{
		for (int f = y + 1; f; f -= f & (-f))
		{
			auto it = fen[e].find(f);
			if (it != fen[e].end())
			{
				res += it -> se;
			}
		}
	}
	return res;
}
void del(int idx, int t)
{
	int lt = *prev(lts.UB(idx)), rt = *rts.LB(idx);
	lts.erase(lt); rts.erase(rt);
	upd(lt, N - 1 - rt, t - lst[lt]);
	if (lt != idx)
	{
		lst[lt] = t;
		lts.insert(lt);
		rts.insert(idx - 1);
	}
	if (rt != idx)
	{
		lst[idx + 1] = t;
		lts.insert(idx + 1);
		rts.insert(rt);
	}
}
void ins(int idx, int t)
{
	if (rts.find(idx - 1) != rts.end() && lts.find(idx + 1) != lts.end())
	{
		int lt = *prev(lts.UB(idx)), rt = *rts.LB(idx);
		rts.erase(idx - 1);
		lts.erase(idx + 1);
		upd(lt, N - idx, t - lst[lt]);
		upd(idx + 1, N - 1 - rt, t - lst[idx + 1]);
		lst[lt] = t;
	}
	else if (rts.find(idx - 1) != rts.end())
	{
		int lt = *prev(lts.UB(idx));
		rts.erase(idx - 1);
		rts.insert(idx);
		upd(lt, N - idx, t - lst[lt]);
		lst[lt] = t;
	}
	else if (lts.find(idx + 1) != lts.end())
	{
		int rt = *rts.LB(idx);
		lts.erase(idx + 1);
		lts.insert(idx);
		upd(idx + 1, N - 1 - rt, t - lst[idx + 1]);
		lst[idx] = t;
	}
	else
	{
		lts.insert(idx);
		rts.insert(idx);
		lst[idx] = t;
	}
}

int32_t main()
{
	ios_base::sync_with_stdio(false); cin.tie(0);
	cout << fixed << setprecision(12);
	cerr << fixed << setprecision(4);
	cin >> N >> Q;
	string temps; cin >> temps;
	FOR(i, 0, N)
	{
		state[i] = (temps[i] == '1');
	}
	FOR(i, 0, N)
	{
		if (state[i] && (i == 0 || !state[i - 1])) lts.insert(i);
		if (state[i] && (i == N - 1 || !state[i + 1])) rts.insert(i);
	}
	for (auto it = lts.begin(); it != lts.end(); it++)
	{
		lst[*it] = -1;
	}
	FOR(i, 0, Q)
	{
		cin >> temps;
		int x, y;
		if (temps[0] == 't')
		{
			cin >> x; x--;
			quer[i] = {-1, x};
		}
		else
		{
			cin >> x >> y; x--; y -= 2;
			quer[i] = {x, y};
		}
	}
	lts.clear(); rts.clear();
	FOR(i, 0, N)
	{
		if (state[i] && (i == 0 || !state[i - 1])) lts.insert(i);
		if (state[i] && (i == N - 1 || !state[i + 1])) rts.insert(i);
	}
	FOR(i, 0, Q)
	{
		if (quer[i].fi == -1)
		{
			int idx = quer[i].se;
			if (!state[idx])
			{
				ins(idx, i);
			}
			else
			{
				del(idx, i);
			}
			state[idx] = state[idx] ^ 1;
		}
		else
		{
			int lt = quer[i].fi, rt = quer[i].se;
			ans = qry(lt, N - 1 - rt);
			auto it = rts.LB(rt);
			if (it != rts.end())
			{
				auto jt = prev(lts.UB(*it));
				if (*jt <= lt)
				{
					int t = lst[*jt];
					ans += (i - t);
				}
			}
			cout << ans << '\n';
		}
	}
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 20 / 20