Submission #428447

#	Time	Username	Problem	Language	Result	Execution time	Memory
428447		errorgorn	Sparklers (JOI17_sparklers)	C++17	50 / 100	236 ms	34132 KiB

sparklers

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

#define ll long long
#define ii pair<ll,ll>
#define fi first
#define se second
#define endl '\n'

#define puf push_front
#define pof pop_front
#define pub push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound

#define rep(x,s,e) for (auto x=s-(s>e);x!=e-(s>e);s<e?x++:x--)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n,k,t;
ll arr[100005];

ii memo[1005][1005];

bool can(ll i){
	rep(x,0,1005) rep(y,0,1005) memo[x][y]=ii(1e10,-1e10);
	
	memo[k][k]=ii(arr[k]-i,arr[k]+i);
	
	rep(x,0,n-1){
		rep(y,1,n-x+1){
			int l=y,r=y+x;
			
			ii temp=memo[l][r];
			temp.fi=max(temp.fi,arr[l-1]-(x+1)*i);
			temp.se=min(temp.se,arr[l-1]+(x+1)*i);
			if (temp.fi<=temp.se){
				memo[l-1][r].fi=min(memo[l-1][r].fi,temp.fi-i);
				memo[l-1][r].se=max(memo[l-1][r].se,temp.se+i);
			}
			
			temp=memo[l][r];
			temp.fi=max(temp.fi,arr[r+1]-(x+1)*i);
			temp.se=min(temp.se,arr[r+1]+(x+1)*i);
			if (temp.fi<=temp.se){
				memo[l][r+1].fi=min(memo[l][r+1].fi,temp.fi-i);
				memo[l][r+1].se=max(memo[l][r+1].se,temp.se+i);
			}
		}
	}
	
	return memo[1][n].fi<=memo[1][n].se;
}

int main(){
	cin.tie(0);
	cout.tie(0);
	cin.sync_with_stdio(false);
	
	cin>>n>>k>>t;
	
	rep(x,1,n+1) cin>>arr[x];
	
	ll lo=-1,hi=1e9,mi;
	while (hi-lo>1){
		mi=hi+lo>>1;
		
		if (can(mi)) hi=mi;
		else lo=mi;
	}
	
	cout<<(hi+t-1)/t<<endl;
}

Compilation message (stderr)

sparklers.cpp: In function 'int main()':
sparklers.cpp:69:8: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |   mi=hi+lo>>1;
      |      ~~^~~

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