poj Monthly Expense

http://poj.org/problem?id=3273

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#define maxn 100010
using namespace std;

int n,s;
int a[maxn];

int main()
{
    while(scanf("%d%d",&n,&s)!=EOF){
    int high=0,low=0;
    for(int i=0; i<n; i++)
    {
        scanf("%d",&a[i]);
        high+=a[i];
        low=max(low,a[i]);
    }
    int mid;
    while(low<=high)
    {
        mid=(high+low)/2;
        int ans=0,sum=0;
        for(int i=0; i<n; i++)
        {
            sum+=a[i];
            if(sum>mid)
            {
                ans++;
                sum=a[i];
            }
        }
        if(sum!=0) ans++;
        if(ans>s)
        {
            low=mid+1;
        }
        else high=mid-1;
    }
    printf("%d
",mid);
    }
    return 0;
}