蓝桥杯备战10.分巧克力

P8647 蓝桥杯 2017 省 AB 分巧克力 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)

暴力枚举 过70%样例

#include<bits/stdc++.h>
#define endl '\n'
#define int long long
using namespace std;
const int N = 2e7+10,M = 1e3+10;
int n,k;
int h[N],w[N];
bool check(int x)
{
	int cnt = 0;
	for(int i=1;i<=n;i++)
	{
		cnt+=(h[i]/x)*(w[i]/x);
	}
	if(cnt>=k)return true;
	else return false;
}
signed main()
{
	std::ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n>>k;
	for(int i=1;i<=n;i++)cin>>h[i]>>w[i];
	int ans = 0;
	for(int i=1;i<=1e5;i++)
	{
		if(check(i))
		ans=i;
	}
	cout<<ans;
	return 0;
}

二分

#include<bits/stdc++.h>
#define endl '\n'
#define int long long
using namespace std;
const int N = 2e7+10,M = 1e3+10;
int n,k;
int h[N],w[N];
bool check(int x)
{
	int cnt = 0;
	for(int i=1;i<=n;i++)
	{
		cnt+=(h[i]/x)*(w[i]/x);
	}
	if(cnt>=k)return true;
	else return false;
}
signed main()
{
	std::ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n>>k;
	for(int i=1;i<=n;i++)cin>>h[i]>>w[i];
	int ans = -1;
	int l = 0,r = 1e5;
	while(l<r)
	{
		int mid = (l+r+1)/2;
		if(check(mid))
		{
			l = mid;
			ans = l;
		}
		else
		{
			r = mid-1;
			ans = r;
		}
	}
	cout<<ans;
	return 0;
}