題目描述
題解
使用二分答案。二分的對象是數段的和,二分的範圍是1-1e10。
代碼如下:
#include<algorithm>
#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<cstring>
using namespace std;
#define ll long long
#define maxn 10000000000
ll read()
{
ll ans=0,sign=1;
char ch;
ch=getchar();
while(ch<'0'||ch>'9')
{
if(ch=='-')
sign=-1;
ch=getchar();
}
while(ch>='0'&&ch<='9')
{
ans=(ans<<1)+(ans<<3)+(ch^48);
ch=getchar();
}
return ans;
}
int n,m;
ll a[100005];
bool cheak(ll tag)
{
ll temp=0;
ll sum=0;
for(int i=1;i<=n;i++)
{
if(temp+a[i]<=tag)
temp+=a[i];
else
{
if(a[i]>tag)
return 0;
temp=a[i];
sum++;
}
}
return (sum+1)<=m;
}
int main()
{
cin>>n>>m;
for(int i=1;i<=n;i++)
a[i]=read();
ll x=1,y=maxn,ans;
while(x<=y)
{
ll mid=x+(y-x)/2;
if(cheak(mid))
{
y=mid-1;
ans=mid;
}
else
x=mid+1;
}
cout<<ans<<'\n';
return 0;
}