POJ3273(最大化问题)

Monthly Expense

Time Limit: 2000MS		Memory Limit: 65536K
Total Submissions: 20603		Accepted: 8101

Description

Farmer John is an astounding accounting wizard and has realized he might run out of money to run the farm. He has already calculated and recorded the exact amount of money (1 ≤ money_i ≤ 10,000) that he will need to spend each day over the next N (1 ≤ N ≤ 100,000) days.

FJ wants to create a budget for a sequential set of exactly M (1 ≤ M ≤ N) fiscal periods called "fajomonths". Each of these fajomonths contains a set of 1 or more consecutive days. Every day is contained in exactly one fajomonth.

FJ's goal is to arrange the fajomonths so as to minimize the expenses of the fajomonth with the highest spending and thus determine his monthly spending limit.

Input

Line 1: Two space-separated integers:  N and  M 
Lines 2.. N+1: Line  i+1 contains the number of dollars Farmer John spends on the  ith day

Output

Line 1: The smallest possible monthly limit Farmer John can afford to live with.

Sample Input

7 5
100
400
300
100
500
101
400

Sample Output

500
题意：将N个数分成M组，使每组之和的最大值最小。

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int MAXN=100005;
int money[MAXN];
int n,m;
bool judge(int d)
{
    int cnt=1;
    int s=0;
    for(int i=0;i<n;i++)
    {
        if(s+money[i]<=d)
        {
            s+=money[i];
        }
        else{
            cnt++;
            s=money[i];
        }
    }
    
    return cnt <= m;
}
int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        int l=0,r=0;
        for(int i=0;i<n;i++)
        {
            scanf("%d",&money[i]);
            r+=money[i];
            l=max(l,money[i]);
        }
        
        while(l<r)
        {
            int mid=(l+r)/2;
            if(judge(mid))//Âú×ãÌõ¼þ,˵Ã÷d>=anserÁË 
                r=mid;
            else l=mid+1;    //dСÁË 
        }        
        printf("%d\n",r);
    }
    
    return 0;
}