Submission #845706

#	Time	Username	Problem	Language	Result	Execution time	Memory
845706		fanwen	Index (COCI21_index)	C++17	110 / 110	1046 ms	245840 KiB

index

#include <bits/stdc++.h>

using namespace std;

#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for (int i = 0, _n = n; i < _n; ++i)
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define FORE(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define debug(...) "[" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }

template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

template <class T>
struct Persistent {
	struct node {
		T val;
		int l, r;
		node (T val = 0, int l = 0, int r = 0) : val(val), l(l), r(r) {}
	};
	vector <node> it;
	vector <int> stt;
	int n, version;

private : 
	void update(int idx, int l, int r, int u, T val) {
		if(l > u || r < u) return;
		int cnt = ++version;
		stt[idx] = cnt;
		if(l == r) {
			it[cnt].val = val;
			return;
		}
		int mid = l + r >> 1;
		update(idx << 1, l, mid, u, val);
		update(idx << 1 | 1, mid + 1, r, u, val);
		it[cnt] = node(it[stt[idx << 1]].val + it[stt[idx << 1 | 1]].val, stt[idx << 1], stt[idx << 1 | 1]);
	}

	T get(int idx, int l, int r, int u, int v) {
		if(l > v || r < u) return 0;
		if(l >= u && r <= v) return it[idx].val;
		int mid = l + r >> 1;
		return get(it[idx].l, l, mid, u, v) + get(it[idx].r, mid + 1, r, u, v);
	}
public :
	
	Persistent(int n = 0) : n(n) {
		version = 0;
		resize(n);
	}

	void resize(int n) {
		it.resize(100 * n + 1);
		stt.resize(n << 2 | 1);
	}

	int update(int u, T val) {
		update(1, 1, n, u, val);
		return stt[1];
	}

	T get(int id, int l, int r) {
		return get(id, 1, n, l, r);
	}

	int size() {
		return n;
	}
};


const int MAXN = 2e5 + 5;

int N, Q, root[MAXN];
pair <int, int> a[MAXN];

void you_make_it(void) {
    cin >> N >> Q;
    FOR(i, 1, N) cin >> a[i].first, a[i].second = i;
    sort(a + 1, a + N + 1);
    Persistent <int> per(N);
    FORD(i, N, 1) {
    	root[i] = per.update(a[i].second, 1);
    }
    while(Q--) {
    	int l, r; cin >> l >> r;
    	int L = 0, R = N;
    	while(R - L > 1) {
    		int mid = L + R >> 1;
    		int id = lower_bound(a + 1, a + N + 1, make_pair(mid, 0)) - a;
    		if(per.get(root[id], l, r) >= mid) L = mid;
    		else R = mid;
    		// cout << debug(root[mid]) << " " << mid << '\n';
    	}
    	cout << L << '\n';
    }
}

signed main() {

#ifdef LOCAL
    freopen("TASK.inp", "r", stdin);
    freopen("TASK.out", "w", stdout);
#endif
    auto start_time = chrono::steady_clock::now();

    cin.tie(0), cout.tie(0) -> sync_with_stdio(0);

    you_make_it();

    auto end_time = chrono::steady_clock::now();

    cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;

    return (0 ^ 0);
}

// Dream it. Wish it. Do it.

Compilation message (stderr)

index.cpp: In function 'void you_make_it()':
index.cpp:94:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   94 |       int mid = L + R >> 1;
      |                 ~~^~~
index.cpp: In instantiation of 'void Persistent<T>::update(int, int, int, int, T) [with T = int]':
index.cpp:63:9:   required from 'int Persistent<T>::update(int, T) [with T = int]'
index.cpp:88:41:   required from here
index.cpp:38:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   38 |   int mid = l + r >> 1;
      |             ~~^~~
index.cpp: In instantiation of 'T Persistent<T>::get(int, int, int, int, int) [with T = int]':
index.cpp:68:13:   required from 'T Persistent<T>::get(int, int, int) [with T = int]'
index.cpp:96:32:   required from here
index.cpp:47:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |   int mid = l + r >> 1;
      |             ~~^~~

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