Submission #356784

#	Time	Username	Problem	Language	Result	Execution time	Memory
356784		YJU	Sparklers (JOI17_sparklers)	C++14	50 / 100	196 ms	65004 KiB

sparklers

#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=2e3+5;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()

ll n,JOI,t,dp[N][N],x[N],u[N];

bool ck(ll k){
	memset(dp,0,sizeof(dp));
	REP1(i,n)x[i]=u[i]-2*k*t*i;
	dp[JOI][JOI]=1;
	for(int L=1;L<=n;L++){
		for(int i=1;i+L-1<=n;i++){
			if(i+L<=n&&x[i]>=x[i+L])dp[i][i+L]|=dp[i][i+L-1];
			if(i-1>=1&&x[i-1]>=x[i+L-1])dp[i-1][i+L-1]|=dp[i][i+L-1];
		}
	}
	return dp[1][n];
}

int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	cin>>n>>JOI>>t;
	REP1(i,n)cin>>u[i];
	ll l=-1,r=1e9+10;
	while(r-l>1){
		ll mid=(l+r)>>1;
		if(ck(mid)){
			r=mid;
		}else{
			l=mid;
		}
	}
	cout<<r<<"\n";
	return 0;
}

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