杭电 4004 大连赛区网络赛。

来源：互联网发布：网络电视怎么关机呢编辑：程序博客网时间：2024/05/04 04:09

#include<iostream>
#include<stdio.h>
#include<algorithm>
using namespace std;
#define INFINITY 2100000000
int a[500001];
int len[500001];
int max(int a,int b)
{
return a>b?a:b;
}
int max_gap;
bool complish(int n,int m,int jump)
{
if(jump<max_gap)
  return false;
int t=jump;
int times=0;
int i;
for(i=1;i<=n;i++)
{

    jump-=len[i];

if(jump<=0||jump-len[i+1]<0||(i==n))
jump=t,times++;

if(times==m&&i!=n)break;
}

if(i<=n)
return false; //跳不过去。
else
return true;
}
int bin(int up,int down,int n,int m)
{

int i,j;
int mid;
while(up>=down)
{
mid=(up+down)/2;
int re=complish(n,m,mid);

  if(!complish(n,m,mid-1)&&re)
  {
   return mid;
  }
  else
  if(re)
  {
   up=mid-1;

  }
  else
  {
   down=mid+1;
  }

}
}
int main()
{
int i,j,k;
int n,m,L;

// freopen("h:\\data.txt","r",stdin);
while(scanf("%d%d%d",&L,&n,&m)!=EOF)
{
  max_gap=-INFINITY;
  for(i=1;i<=n;i++)
    scanf("%d",&a[i]);
  sort(a+1,a+n+1);

  for(i=1;i<=n;i++)
  {
    len[i]=a[i]-a[i-1];
    if(len[i]>max_gap)
    max_gap=a[i]-a[i-1];

  }
  len[n+1]=L-a[n];
  if(len[n+1]>max_gap)
   max_gap=len[n+1];
        cout<<bin(L,max(max_gap,L/m),n+1,m)<<endl;

}

}