跳石头

#include<bits/stdc++.h>
using namespace std;
#define  ll long long
#define maxn 100000000
ll l,m,n,a[maxn],ans;
int judge(ll x)
{
    ll s=0,cnt=0;
    for(ll i=1;i<=m+1;i++)
    {
        if(a[i]-s<x)cnt++;
        else s=a[i];
    }
    if(cnt>n)return 0;
    else return 1;
}
int main()
{
cin>>l>>m>>n;
for(ll i=1;i<=m;i++)
{
    cin>>a[i];
}
a[m+1]=l;
ll left=1,right=l;
while(left<=right)  //二分模板
{
    ll mid=(left+right)/2;
    if(judge(mid))
    {
        left=mid+1;
        ans=mid;
    }
    else
    {
        right=mid-1;
    }
}
cout<<ans;
    return 0;
}