Submission #799462

#	Time	Username	Problem	Language	Result	Execution time	Memory
799462		bachhoangxuan	Sparklers (JOI17_sparklers)	C++17	0 / 100	0 ms	212 KiB

sparklers

// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
- insert(x),erase(x)
- find_by_order(k): return iterator to the k-th smallest element
- order_of_key(x): the number of elements that are strictly smaller
*/
#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<int,pii>
#define mpp make_pair
#define fi first
#define se second
const int inf=1e18;
const int mod=998244353;
const int maxn=200005;
const int bl=650;
const int maxs=655;
const int maxm=200005;
const int maxq=500005;
const int maxl=20;
const int maxa=250000;
const int root=3;
int power(int a,int n){
    int res=1;
    while(n){
        if(n&1) res=res*a%mod;
        a=a*a%mod;n>>=1;
    }
    return res;
}
const int iroot=power(3,mod-2);
const int base=101;

void solve(){
    int n,k,t;cin >> n >> k >> t;
    vector<int> x(n+1);
    for(int i=1;i<=n;i++) cin >> x[i];
    auto f = [&](vector<int> a,vector<int> b){
        if(a[0]<b[0]) return false;
        int i=1,j=1,mn=b[0],mx=a[0];
        while(true){
            if(i<(int)a.size() && a[i]>=mn) mx=max(mx,a[i++]);
            else if(j<(int)b.size() && b[j]<=mx) mn=min(mn,b[j++]);
            else break;
        }
        return (i==(int)a.size() && j==(int)b.size());
    };
    auto check = [&](int m){
        vector<int> a,b;
        for(int i=k;i>=1;i--) a.push_back(x[i]-2*m*t*i);
        for(int i=k;i<=n;i++) b.push_back(x[i]-2*m*t*i);
        if(f(a,b)) return true;
        reverse(a.begin(),a.end());
        reverse(b.begin(),b.end());
        return f(a,b);
    };
    int l=0,r=1e9,res=1e9;
    while(r>=l){
        int mid=(l+r)>>1;
        if(check(mid)) res=mid,r=mid-1;
        else l=mid+1;
    }
    cout << res << '\n';
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    int test=1;//cin >> test;
    while(test--) solve();
}

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