Submission #607783

#	Time	Username	Problem	Language	Result	Execution time	Memory
607783		cheissmart	Teams (IOI15_teams)	C++14	34 / 100	4059 ms	102076 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[N], r[N];
vi p;

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 r_r = r - tl + 1 - r_l;
		int l_l = (l ? p[lv][l - 1] : 0) - (tl ? p[lv][tl - 1] : 0);
		int l_r = l - 1 - tl + 1 - l_l;
		return qry(tl + l_l, tl + r_l - 1, x, tl, tm, lv + 1)
			 + qry(tm + l_r, tm + r_r - 1, x, tm, tr, lv + 1);
	}
	int find_who(int l, int r, int need, int tl = 0, int tr = n, int lv = 0) { // [l, r], [tl, tr)
		vi b;
		for(int i = l; i <= r; i++)
			b.PB(a[i]);
		sort(ALL(b));
		return b[need - 1];
		// assert(need <= r - l + 1);
		// if(tr - tl == 1) return b[tl];
		// int tm = (tl + tr) / 2;
		// int r_l = p[lv][r] - (tl ? p[lv][tl - 1] : 0);
		// int r_r = r - tl + 1 - r_l;
		// int l_l = (l ? p[lv][l - 1] : 0) - (tl ? p[lv][tl - 1] : 0);
		// int l_r = l - 1 - tl + 1 - l_l;
		// if(r_l - l_l >= need)
		// 	return find_who(tl + l_l, tl + r_l - 1, need, tl, tm, lv + 1);
		// else
		// 	return find_who(tm + l_r, tm + r_r - 1, need - (r_l - l_l), tl, tm, lv + 1);
	}
}

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 need) {
	lb = as_lb[lb], rb = as_rb[rb];
	assert(lb <= rb);
	return wt::find_who(lb, rb, need + 1); // [lb, rb]
} 
 
void init(int _n, int _l[], int _r[]) {
	n = _n;
	for(int i = 0; i < n; i++)
		l[i] = _l[i], r[i] = _r[i];
 
	p = vi(n); iota(ALL(p), 0);
	sort(ALL(p), [&] (int x, int y) {
		return r[x] < r[y];
	});
	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] = lower_bound(ALL(aux), pi(i, -INF)) - aux.begin();
		as_rb[i] = upper_bound(ALL(aux), pi(i, INF)) - aux.begin() - 1;
	}
}

struct seg {
	int r, hi;
};
 
int can(int m, int a[]) {
	if(accumulate(a, a + m, 0LL) > n) return 0;
	sort(a, a + m);
 
	V<seg> stk;
	stk.PB({0, n});
	for(int i = 0, j = 0; i < m; i++) {
		int need = 0, ii = i;
		while(i < m && a[i] == a[ii]) need += a[i++];
		i--;

		while(j < n && r[p[j]] < a[i]) j++;
		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, need + dead);
				stk.PB({a[i], who});
				break;
			}
		}
		if(stk.empty()) return 0;
	}
	return 1;
}

Compilation message (stderr)

teams.cpp: In function 'int wt::find_who(int, int, int, int, int, int)':
teams.cpp:61:6: warning: declaration of 'b' shadows a global declaration [-Wshadow]
   61 |   vi b;
      |      ^
teams.cpp:27:6: note: shadowed declaration is here
   27 |  int b[N]; // sorted a
      |      ^
teams.cpp:60:43: warning: unused parameter 'tl' [-Wunused-parameter]
   60 |  int find_who(int l, int r, int need, int tl = 0, int tr = n, int lv = 0) { // [l, r], [tl, tr)
      |                                       ~~~~^~~~~~
teams.cpp:60:55: warning: unused parameter 'tr' [-Wunused-parameter]
   60 |  int find_who(int l, int r, int need, int tl = 0, int tr = n, int lv = 0) { // [l, r], [tl, tr)
      |                                                   ~~~~^~~~~~
teams.cpp:60:67: warning: unused parameter 'lv' [-Wunused-parameter]
   60 |  int find_who(int l, int r, int need, int tl = 0, int tr = n, int lv = 0) { // [l, r], [tl, tr)
      |                                                               ~~~~^~~~~~
teams.cpp: In function 'void init(int, int*, int*)':
teams.cpp:111:49: warning: conversion from '__gnu_cxx::__normal_iterator<std::pair<int, int>*, std::vector<std::pair<int, int> > >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
  111 |   as_lb[i] = lower_bound(ALL(aux), pi(i, -INF)) - aux.begin();
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
teams.cpp:112:62: warning: conversion from '__gnu_cxx::__normal_iterator<std::pair<int, int>*, std::vector<std::pair<int, int> > >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
  112 |   as_rb[i] = upper_bound(ALL(aux), pi(i, INF)) - aux.begin() - 1;
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~

• Subtask 1: 21 / 21
• Subtask 2: 13 / 13
• Subtask 3: 0 / 43
• Subtask 4: 0 / 23