#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int L,n,m;
int a[N],l,r,ans;
bool check(int mid){
	int last=0;
	int sum=0;
	for(int i=1;i<=n;i++){
		if(a[i]-last<mid){
			sum++;
		}
		else{
			last=a[i];
		}
	}
	return sum<=m;
}
int main(){
	cin>>L>>n>>m;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	a[++n]=L;
	r=L;
	while(l<=r){
		int mid=l+r>>1;
		if(check(mid)){
			ans=mid;
			l=mid+1;
		}
		else
			r=mid-1;
	}
	cout<<ans;

}
小鸟

/*****************************************
备注：
******************************************/
#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int main()
{
	while(l < r) // 最小值的最大值
	{
		int mid = l + r + 1 >> 1;
		if(cheak(mid))
			l = mid;
		else 
			r = mid -1 ;
	}
	cout << l << endl;


	while(l < r) // 最大值的最小值
	{
		int mid = l + r >> 1;
		if(cheak(mid))
			r = mid;
		else 
			l = mid + 1;
	}
	cout << r << endl;


	while(l <= r) // 二分搜索
	{
		int mid = l + r >> 1;
		if(a[mid] == k)
		{
			cout << mid ;
			break;
		}
		else if(a[mid] > k) 
		{
			r = mid - 1;
		}
		else 
		{
			l = mid + 1;
		}
	}
	return 0;
}

#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e6 + 10;
const int INF = 0x3f3f3f3f;
LL a[N];
LL k, n,m;
bool cheak(int x)
{
	int pre=0;
	int sum = 0;
	for(int i=1;i<=n;i++)
	{
		if(a[i]-pre<x)
			sum++;
		else
			pre=a[i];
		if(sum>m)
			return false; 
	}
	return true;
}
int find()
{
	int l,r;
	l=1,r=k;
	while(l<r)
	{
		int mid=l+r+1>>1;
		if(cheak(mid))
			l=mid;
		else
			r=mid-1;
	}
	return l;
}
int main()
{
	cin >>k>>n>>m;
	for(int i=1;i<=n;i++)
		scanf("%lld",&a[i]);
	a[0]=0;
	a[++n]=k;
	cout << find()<<endl;
	return 0; 
}

/*
int      %o/%lo 8 %d/%i/%ld/%li 10 %x/%lx 16
longlong %lld
float    %f/%e
double   %lf/%le
char     %c
char[]   %s
'a'=97
'z'=122
'A'=65
'Z'=90
'0'=48
'9'=57
*/
#include <iostream>
#include <iomanip>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <ctime>
#include <limits>
#include <assert.h>
#include <stdlib.h>
using namespace std;
#define LL long long
#define ull unsigned long long
const int N=1e5+10;
const int INF=0x3f3f3f3f;
const double pi=3.1416;
int L,n,m,a[N],ans,l,r;
bool check(int mid){
	int last=0,sum=0;
	for(int i=1;i<=n;i++){
		if(a[i]-last<mid){
			sum++;
		}else{
			last=a[i];
		}
	}
	return sum<=m;
}
int main(){
	cin>>L>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	a[++n]=L;
	l=1,r=L;
	while(l<=r){
		int mid=(l+r)>>1;
		if(check(mid)){
			ans=mid;
			l=mid+1;
		}else{
			r=mid-1;
		}
	}
	cout<<ans;
return 0;
}

#include

#include

#include

#include

#include

#include

using namespace std;

const int N = 5e4 +10;

const int INF=0x3f3f3f;

int n,mid,m,a[N],l,r,ans,L;

bool check(int k){

int last = 0;

int sum = 0;

for(int i = 1;i<=n;i++){

if(a[i] - last < k)

sum++;

else

last = a[i];

}

return sum <= m;

}

int main(){

cin>>L>>n>>m;

for(int i = 1;i<=n;i++)

cin>>a[i];

a[++n] = L;

r = L;

while(l<=r){

int mid = l + r >>1;

if(check(mid)){

ans = mid;

l = mid + 1;

}

else

r = mid - 1;

}

cout<<ans;

}

#include <bits/stdc++.h> using namespace std; int L,n,m; const int N=1e5+10; int a[N],l,r,ans; bool check(int mid){ int last = 0; int sum=0; for(int i=1;i<=n;i++) if(a[i]-last<mid){ sum++; } else{ last=a[i]; }

return sum<=m;

} int main(){ cin>>L>>n>>m; for(int i=1;i<=n;i++){ cin>>a[i]; } a[++n]=L; r=L; while(l<=r){ int mid=l+r>>1; if(check(mid)){ ans=mid; l=mid+1; } else{ r=mid-1; } } cout<<ans; return 0;

}

#include<bits/stdc++.h>
using namespace std;
int L,n,m,a[100000];
int p(int x){
    int p=0,q=0;
    for(int i=1;i<=n;i++)
    if(a[i]-p<x)q++;
    else p=a[i];
    return q;
}
int main(){
    cin>>L>>n>>m;
    for(int i=1;i<=n;i++)
    cin>>a[i];
    a[++n]=L;
    int l=0,r=L;
    int ans=-111;
    while(l<=r){
        int mid=(l+r)/2;
        int x=p(mid);
        if(x<=m)l=mid+1,ans=mid;
        else r=mid-1;
    }
    cout<<ans;
}

/*****************************************
备注：
******************************************/
#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
LL n,m,k;
LL a[N];
bool cheak(int mid)
{
	int pre=0;
	int cnt=0;
	for(int i=1;i<=m+1;i++)
	{
		if(a[i]-pre<mid)
		{
			cnt++;
			if(cnt>k)
				return false;
		}
		else
			pre=a[i];
	}
	return true;
}
int main()
{
	cin>>n>>m>>k;
	for(int i=1;i<=m;i++)
		cin>>a[i];
	a[0]=0;
	a[m+1]=n;
	LL l=1,r=n;
	while(l<r)
	{
		LL mid=l+r+1>>1;
		if(cheak(mid))
		{
			l=mid;
		}
		else
			r=mid-1;	
	}
	cout<<l<<endl;
	return 0;
}