Submission #608383

#	Time	Username	Problem	Language	Result	Execution time	Memory
608383		cheissmart	Teams (IOI15_teams)	C++14	100 / 100	2723 ms	107960 KiB

teams

#include "teams.h"
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define F first
#define S second
#define V vector
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(), (v).end()
 
using namespace std;
 
typedef long long ll;
typedef pair<int, int> pi;
typedef V<int> vi;
 
const int INF = 1e9 + 7, N = 5e5 + 7;
 
int n;
int *l, *r;
int p[N], rp[N];
 
namespace wt { // wavelet tree
	int a[N]; // a is a permutation
	int b[N]; // sorted a
	int t[20][N], p[20][N];
 
	void build(int tl, int tr, int lv) {
		if(tr - tl == 1) return;
		int tm = (tl + tr) / 2, mid = b[tm];
		int lbuf = tl, rbuf = tm;
		for(int i = tl; i < tr; i++) {
			if(t[lv][i] < mid) t[lv + 1][lbuf++] = t[lv][i], p[lv][i] = 1;
			else t[lv + 1][rbuf++] = t[lv][i];
			p[lv][i] += i ? p[lv][i - 1] : 0;
		}
		build(tl, tm, lv + 1);
		build(tm, tr, lv + 1);
	}
	void build() {
		for(int i = 0; i < n; i++) {
			b[i] = i;
			t[0][i] = a[i];
		}
		build(0, n, 0);
	}
	int qry(int l, int r, int x, int tl = 0, int tr = n, int lv = 0) { // [l, r], [tl, tr)
		if(b[tl] >= x || l > r) return 0;
		if(b[tr - 1] < x) return r - l + 1;
		int tm = (tl + tr) / 2;
		int r_l = p[lv][r] - (tl ? p[lv][tl - 1] : 0);
		int l_l = (l ? p[lv][l - 1] : 0) - (tl ? p[lv][tl - 1] : 0);
		return qry(tl + l_l, tl + r_l - 1, x, tl, tm, lv + 1)
			 + qry(tm + l - 1 - tl + 1 - l_l, tm + r - tl + 1 - r_l - 1, x, tm, tr, lv + 1);
	}
	int find_who(int l, int r, int at_least, int need) { // [l, r]
		int lb = at_least, rb = n - 1;
		while(lb <= rb) {
			int mb = (lb + rb) / 2;
			if(qry(l, r, mb + 1) >= need + 1) rb = mb - 1;
			else lb = mb + 1;
		}
		return lb;
	}
}
 
V<pi> aux;
int as_lb[N], as_rb[N];
 
int qry(int lb, int rb, int x) { // # of elements < x in [lb, rb]
	lb = as_lb[lb], rb = as_rb[rb];
	if(lb > rb) return 0;
	return wt::qry(lb, rb, x); // [lb, rb]
}
 
int find_who(int lb, int rb, int at_least, int need) {
	lb = as_lb[lb], rb = as_rb[rb];
	assert(lb <= rb);
	return wt::find_who(lb, rb, at_least, need); // [lb, rb]
} 
 
void init(int _n, int _l[], int _r[]) {
	n = _n;
	l = _l, r = _r;

	iota(p, p + n, 0);
	sort(p, p + n, [&] (int x, int y) {
		return r[x] < r[y];
	});
	for(int i = 0; i < n; i++)
		rp[i] = r[p[i]];
	for(int i = 0; i < n; i++)
		aux.EB(l[p[i]], i);
	sort(ALL(aux));
	for(int i = 0; i < n; i++)
		wt::a[i] = aux[i].S;
	wt::build();
	for(int i = 1; i <= n; i++) {
		as_lb[i] = as_lb[i - 1];
		while(as_lb[i] < n && aux[as_lb[i]].F < i) as_lb[i]++;
		as_rb[i] = as_rb[i - 1];
		while(as_rb[i] + 1 < n && aux[as_rb[i] + 1].F <= i) as_rb[i]++;
	}
}
 
struct seg {
	int r, hi;
};
V<seg> stk;
 
int can(int m, int a[]) {
	if(accumulate(a, a + m, 0LL) > n) return 0;
	sort(a, a + m);
	stk.clear(); 
	stk.PB({0, n});
	for(int i = 0; i < m; i++) {
		int need = 0, ii = i;
		while(i < m && a[i] == a[ii]) need += a[i++];
		i--;
 
		int j = lower_bound(rp, rp + n, a[i]) - rp
		;
		while(stk.back().hi < j) {
			assert(SZ(stk));
			stk.pop_back();
		}
		int at_least = j;
		while(need && SZ(stk)) {
			int lb = stk.back().r, rb = a[i]; // (lb, rb]
			int cnt = qry(lb + 1, rb, stk.back().hi) - qry(lb + 1, rb, at_least);
			if(cnt < need) {
				at_least = stk.back().hi;
				stk.pop_back();
				need -= cnt;
			} else if(cnt == need) {
				at_least = stk.back().hi;
				stk.pop_back();
				stk.PB({a[i], at_least});
				need -= cnt;
				break;
			} else {
				int dead = qry(lb + 1, rb, at_least);
				int who = find_who(lb + 1, rb, at_least, need + dead);
				stk.PB({a[i], who});
				break;
			}
		}
		if(stk.empty()) return 0;
	}
	return 1;
}

Compilation message (stderr)

teams.cpp: In function 'int can(int, int*)':
teams.cpp:123:41: warning: conversion from 'long int' to 'int' may change value [-Wconversion]
  123 |   int j = lower_bound(rp, rp + n, a[i]) - rp
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

• Subtask 1: 21 / 21
• Subtask 2: 13 / 13
• Subtask 3: 43 / 43
• Subtask 4: 23 / 23