Submission #1260956

#	Time	Username	Problem	Language	Result	Execution time	Memory
1260956		tminh	Index (COCI21_index)	C++20	110 / 110	2040 ms	19108 KiB

index

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

#define task ""
#define ll long long
#define endl '\n'
#define fi first
#define se second
#define vall(a) (a).begin(), (a).end()
#define sze(a) (int)a.size()
#define pii pair<int, int>
#define pll pair<ll, ll>


#define ep emplace_back
#define pb push_back
#define pf push_front


const ll mod = 1e9 + 7;
const int N = 2e5 + 5;
const ll oo = 1e18;

bool START;

int n, q; 
int a[N];

struct BIT {
	vector<int> bit[N];
	void add(int idx, int val) {
		for (;idx <= n; idx += idx & -idx) bit[idx].pb(val);
	}
	int get(int idx, int val) {
		int ans = 0;
		for (; idx > 0; idx -= idx & -idx) ans += (bit[idx].end() - lower_bound(vall(bit[idx]), val));
		return ans;
	}
	int get(int l, int r, int val) {
		return get(r, val) - get(l - 1, val);
	}
} bit;


bool check(int x, int l, int r) {
	return bit.get(l, r, x) >= x;
}

inline void solve() {
	for (int i = 1; i <= n; ++i) bit.add(i, a[i]);
	for (int i = 1; i <= n; ++i) sort(vall(bit.bit[i]));
	
	
	while(q--) {
		int L, R;
		cin >> L >> R;
		
		int l = 0, r = R - L + 1, ans = 0;
		while(l <= r) {
			int mid = (l + r) >> 1;
			if (check(mid, L, R)) {
				ans = mid;
				l = mid + 1;
			} else {
				r = mid - 1;
			}
		}
		cout << ans << endl;
	}
}


inline void input() {
    cin >> n >> q;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    return solve();
}
bool END;

int main() {
    if(fopen(task ".inp", "r")) {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);

    input();
    
    
    cerr << endl << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << 's' << endl;
    cerr << "Memory: " << fabs ((&END - &START)) / 1048576.0 << "MB\n";
    return 0;
}

Compilation message (stderr)

index.cpp: In function 'int main()':
index.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
index.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 50 / 50