Submission #410675

#	Time	Username	Problem	Language	Result	Execution time	Memory
410675		dynam1c	Street Lamps (APIO19_street_lamps)	C++17	20 / 100	223 ms	12144 KiB

street_lamps

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

#define endl "\n"
#define all(c) (c).begin(),(c).end()

// when you ponder, divide and conquer

struct RMQ {
	int n;
	vector<int> seg;
	RMQ(vector<int> arr) : n(arr.size()), seg(2*n) {
		for (int i = 0; i < n; i++)
			seg[i+n] = arr[i];
		for (int i = n-1; i > 0; i--)
			seg[i] = max(seg[i<<1], seg[i<<1|1]);
	}
	int query(int l, int r) {
		int acc = INT_MIN;
		for (l += n, r += n; l != r; l >>= 1, r >>= 1) {
			if (l&1) acc = max(acc, seg[l++]);
			if (r&1) acc = max(acc, seg[--r]);
		}
		return acc;
	}
	void update(int i, int x) {
		for (seg[i += n] = x; i > 1; i >>= 1)
			seg[i>>1] = max(seg[i], seg[i^1]);
	}
};

signed main() {
	// freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	
	int n, q;
	cin >> n >> q;
	string s;
	cin >> s;
	vector<int> time(n);
	for (int i = 0; i < n; i++)
		time[i] = s[i] == '1' ? 0 : 1e6;
	RMQ rmq(time);
	for (int qq = 0; qq < q; qq++) {
		string t;
		cin >> t;
		if (t == "query") {
			int l, r;
			cin >> l >> r;
			l--, r--;
			cout << max(qq+1 - rmq.query(l, r), 0) << endl;
		}
		if (t == "toggle") {
			int i;
			cin >> i;
			i--;
			rmq.update(i, qq+1);
		}
	}
}
/* --- PSolving ---
 * Simplifying (getting rid of variables, conditions, code logic, etc.)
 * Reframing
 * Solving a subtask (subgoal, aux. problem, removing a condition or fixing a parameter, etc.)
 * Inducing
 * Divide and conquer
 * Working backwards
 * Visual intuition
 * !! Reductions don't have to be specializations, they can be generalizations
 */

• Subtask 1: 0 / 20
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20