1247：河中跳房子_1247:河中跳房子

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#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>
#include <string>
#include <cmath>
#include <map>
#include <set>
#include <queue>
#define sf(a) scanf("%d\n",&a)
#define E 1e-8
#define pi acos(-1.0)
#define ms(a) memset(a,0,sizeof a)
#define rep(a,b,c) for(int a=b;a<=c;a++)
#define pf(a) printf("%.3lf\n",a)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int inf=0x3f3f3f3f;
const int idata=1e6+5;
 
int i,j,k;
//int judge,flag;
ll step[idata];
//ll dp[idata][10];
ll temp;
ll n,m,t;
ll maxx=0,minn=inf;
ll cnt,len,sum,ans;
ll high,wigh;
//map<ll,int>pre[2];
set<ll>s;
//priority_queue<ll, vector<ll>,less<ll> >q;
queue<ll>q;
 
bool check(int aim)
{
    int temp=0;//目前位置
    int ans=0;
    rep(i,1,n)
    {
        if(step[i]-temp<aim)//将石头删掉
            ans++;
        else
            temp=step[i];
    }
    if(m-temp<aim) ans++;
    return ans<=k;
}
int main()
{
    while(cin>>m>>n>>k)
    {
        rep(i,1,n)
        {
            cin>>step[i];
        }
        int l=0,r=m;
        while(r-l>1)
        {
            int mid=(l+r)/2;
            if(check(mid))
                l=mid;
            else
                r=mid;
        }
        cout<<l<<endl;
    }
    return 0;
}