poj 3273 分期问题 最大化最小值

题意：将N个账款分给城M个财务期，使得每个分期账款和的值最大？

思路：

1. 每次mid为分期账款
2. 如果分期次数小于m说明mid太大，减上限  反正 增下限
3. 开始下限设为 最大值 上限设为和

解决问题的代码：

#include<iostream>
#include<cstdio>
#include<cstring>
#include <algorithm>
using namespace std;
int n, m;
int a[100005];
bool Judge(int mid)
{
        int sum = 0, num = 1;//查询每组上限为mid的情况下的组数
        for (int i = 1; i <= n; i++)
        {
               if (sum + a[i] <= mid)
                       sum += a[i];
               else
               {
                       sum = a[i];
                       num++;
               }
        }
        if (num > m)//组数偏大，说明mid偏小
               return true;
        else
               return false;
}
int main()
{
        cin >> n >> m;
        int maxn = -1, sum = 0;
        for (int i = 1; i <= n; i++)
        {
               scanf("%d", &a[i]);
               maxn = max(maxn, a[i]);
               sum += a[i];
        }
        int low = maxn, high = sum;
        int mid = (low + high) / 2;
        while (low < high)
        {
               if (Judge(mid))
                       low = mid + 1;
               else
                       high = mid - 1;
               mid = (low + high) / 2;
        }
        printf("%d\n", mid);
        return 0;
}