【二分答案】bzoj1639 [Usaco2007 Mar]Monthly Expense 月度开支

#include<cstdio>
using namespace std;
#define N 100001
int n,m,a[N];
bool check(int x)
{
	int now=0,sum=1;
	for(int i=1;i<=n;++i)
	  {
	  	if(now+a[i]<=x) now+=a[i];
	  	else
	  	  {
	  	  	now=a[i];
	  	  	++sum;
	  	  	if(now>x||sum>m)
	  	  	  return 0;
	  	  }
	  }
	return 1;
}
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;++i) scanf("%d",&a[i]);
	int l=1,r=1000000000;
	while(r>l)
	  {
	  	int mid=(l+r>>1);
	  	if(check(mid)) r=mid;
	  	else l=mid+1;
	  }
	printf("%d\n",l);
	return 0;
}