Submission #878967

#	Time	Username	Problem	Language	Result	Execution time	Memory
878967		eitanelb	Sparklers (JOI17_sparklers)	C++14	50 / 100	153 ms	262144 KiB

sparklers

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

bool ok(int n, int k, vector<int>&v, ll m){
    bool dp[n][n];
    for(int i=0;i<n;i++)for(int j=0;j<n;j++) dp[i][j]=0;
    dp[k-1][k-1]=1;
    for(int sz=2;sz<=n;sz++){
        for(int i=0;i+sz-1 < n;i++){
            if(((v[i+sz-1]-v[i]) <= 2*m*(sz-1)) && (dp[i][i+sz-2] || dp[i+1][i+sz-1])) dp[i][i+sz-1]=1;
        }
    }
    //cout<<m<<' '<<dp[0][n-1]<<endl;
    return dp[0][n-1];
}
int func(int n, int k, int t, vector<int>&v){
    int s=0, e=1e9, m;
    while(e>s){
        m = (e+s)/2;
        if(ok(n,k,v,m)) e=m;
        else s=m+1;
    }
    return (s+t-1)/t;
}

int main(){
    ios::sync_with_stdio(0); cin.tie(0);
    int n,k,t;
    cin>>n>>k>>t;
    vector<int> v(n);
    for(int i=0;i<n;i++) cin>>v[i];
    
    int res = func(n,k,t,v);
    
    cout<<res<<endl;
}

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