Codeforces Round #521 (Div. 3) D.Cutting Out

原题:https://codeforces.com/contest/1077/problem/D

题意:根据给出的长度k,要求从原数列中找出一个长度为k且可以重复最多次的数列。

思路:二分查找重复次数,每个数需要出现的次数就是他的个数除重复次数,比如1 3 1 3 10 3 7 7 12 3
原数列中有4个3，当查找可重复2次的数列时，3就需要出现2次，即4/2.

#include<iostream>
#include<queue>
#include<cmath>
#include<algorithm>
#include<bitset>
#include<vector>
using namespace std;
long long int n, k;
const int maxn = 2e6 + 5;
int counts[maxn];
int team[maxn];
bool check(int x)
{
	int temp = 0;
	if (x == 0)
		return false;
	for (int i = 1; i <= 2e5; i++)
	{
		for (int j = 1; j <= team[i]/ x; j++)
		{
			counts[++temp] = i;
		}
	}
	return temp >= k;
}
int main()
{
	cin >> n >> k;
	for (int i = 1; i <= n; i++)
	{
		int num;
		cin >> num;
		team[num]++;
	}
	int left = 1, right = 2e6, ans = 0;
	while (left < right)
	{
		int mid = (left + right) / 2;
		if (check(mid))
		{
			left = mid + 1;
			ans = mid;
		}
		else
		{
			right = mid;
		}
	}
	check(ans);
	for (int i = 1; i <= k; i++)
		cout << counts[i] << " ";
}