poj 3273 Monthly Expense(二分查找)

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cmath>

using namespace std;

int a[100010];
int N,M;

bool f(int mid)         //最小值为mid的时的个数
{
int sum=0;
int len=1;
for(int i=1;i<=N;i++)
{
if(sum+a[i]<=mid)
{
sum+=a[i];
}
else
{
sum=a[i];
len++;
}
}
if(len>M) return false;
else return true;
}

int main(int argc, char const *argv[])
{
while(cin>>N>>M)
{
double high=0,low=0;
for(int i=1;i<=N;i++)
{
cin>>a[i];
high+=a[i];
if(low<a[i])
{
low=a[i];
}
}
int mid=(low+high)/2;
while(low<high)
{

if(!f(mid))
{
low=mid+1;
}
else
{
high=mid-1;
}
mid=(low+high)/2;
}
cout<<mid<<endl;
}
return 0;
}