Submission #200621

#	Time	Username	Problem	Language	Result	Execution time	Memory
200621		gs18115	Sparklers (JOI17_sparklers)	C++14	0 / 100	6 ms	380 KiB

sparklers

#include<iostream>
#include<vector>
#include<algorithm>
#define ep emplace
#define eb emplace_back
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define semicolon ;
#define ryan bear
using namespace std;
typedef long long ll;
typedef pair<int,int>pi;
typedef pair<ll,ll>pl;
const int inf=1e9+7;
const ll INF=1e18;
int n,k;
ll x[100010];
bool dp[1010][1010];
inline bool able(ll s)
{
    for(int i=0;i<n;i++)
        dp[i][i]=i==k-1?1:0;
    for(int l=1;l<n;l++)
    {
        for(int i=0;i+l<n;i++)
        {
            int j=i+l;
            dp[i][j]=(dp[i+1][j]||dp[i][j-1])&&x[i]+s*l>=x[j]-s*l;
        }
    }
    return dp[0][n-1];
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ll t;
    cin>>n>>k>>t;
    for(int i=0;i<n;i++)
        cin>>x[i];
    ll s=1;
    ll e=inf;
    while(s<e)
    {
        ll m=s+e>>1;
        if(able(m))
            e=m;
        else
            s=m+1;
    }
    cout<<(s+t-1)/t<<endl;
    return 0;
}

Compilation message (stderr)

sparklers.cpp: In function 'int main()':
sparklers.cpp:46:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         ll m=s+e>>1;
              ~^~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50