poj-3258-二分

所谓二分感觉用的很多，题比较难看出二分的意思。
总之让求最极限的解比如最大最小解时数据量太大时考虑首先想到二分啊

#include<cstdio>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<set>
#include<map>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<ctime>
using namespace std;
int a[60000],n,minn,m,l;
bool toJudge(int all)
{
    bool sym = true;
    int pre = 0,s = 0;
    for(int i=1;i<=n;i++)
    {
      pre+=(a[i]-a[i-1]);
      if(pre<all)s++;
      else pre = 0;
    }
    if(s>m)sym = false;
    return sym;
}
void bin(int left,int right)
{
    while(left<=right)
    {
        int mid = (left+right)/2;
        if(toJudge(mid)){
            minn = mid;
            left = mid+1;
        }
        else{
            right = mid-1;
        }
    }
}
int main()
{
    while(scanf("%d%d%d",&l,&n,&m)!=EOF)
    {
       for(int i=1;i<=n;i++)
        scanf("%d",&a[i]);
       sort(a+1,a+n+1);
       minn = 200000000;
       bin(1,l);
       printf("%d\n",minn);
    }
    return 0;
}