Submission #864559

#	Time	Username	Problem	Language	Result	Execution time	Memory
864559		manizare	Sparklers (JOI17_sparklers)	C++14	0 / 100	1 ms	2648 KiB

sparklers

#include <bits/stdc++.h> 
 
#pragma GCC optimize("O3,unroll-loops")
#define pb push_back
#define F first
#define S second 
#define all(a) a.begin(),a.end()
#define pii pair <int,int>
#define Pii pair< pii , pii >
#define int long long
#define ld long double 
using namespace std ;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 6e5 + 10 , sq = 3 , maxq = 1e7 + 1 ,  inf = 1e18 + 10 , mod= 998244353 ,lg = 20 ;
int n ,t , k;
vector <ld> a , b ;
int x[maxn] ; 
ld pa[maxn] , pb[maxn] , ma[maxn] , mb[maxn] ; 
int sl(){
  ld sm = 0 , sm2 , val =0  ;int l = 1 ; 
  for(int i =1 ; i < a.size() ; i++){
    sm += a[i];
    if(sm >= 0){
      val += sm ;
      sm = 0 ;
      l = i+1 ;
    }
  }
  sm2 = sm  ;
  sm = 0 ;int l2 = 1 ;
  for(int i = 1 ;i < b.size() ; i++){
    sm += b[i] ;
    if(sm >= 0){
      val += sm ;
      sm =0 ;
      l2 = i+1 ;
    }
  }
  ld val2 = val; 
  bool ok1 = 1 , ok2 = 1;
  for(int i = l ; i < a.size() ; i++){
    val2 += a[i] ;
    if(val2 < 0)ok1 = 0 ;
  }
  for(int i = l2 ; i < b.size() ; i++){
    val2 += b[i] ;
    if(val2 < 0)ok1 =0 ; 
  }
  for(int i = l2 ; i < b.size() ; i++){
    val += b[i] ;
    if(val < 0)ok2 =0 ;
  }
  for(int i = l ; i < a.size() ; i++){
    val += a[i] ;
    if(val < 0)ok2 =0 ;
  }
  return ok1|ok2 ;
}

bool ch(int z){
  a.clear();b.clear();
  a.pb(0);
  b.pb(0) ;
  a.pb((ld)t); 
  for(int i = k+1; i <= n ; i++){
    a.pb(-(ld)(x[i] - x[i-1])/(ld)(2*(ld)z));
    a.pb((ld)t) ;
  }
  for(int i = k-1 ; i >= 1; i--){
    b.pb(-(ld)(x[i+1] - x[i])/(ld)(2*(ld)z));
    b.pb((ld)t) ;
  }
  return sl() ;
}

signed main() {
  ios::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0) ;

  cin >> n >> k >> t ;
  for(int i = 1; i <= n ; i++){
    cin >> x[i] ;
  }
  int l = 0 , r = 1e9 ; 
  while(r-l>1){
    int mid = (l+r)/2 ;
    if(ch(mid) == 1)r= mid ;
    else l = mid ;
  }
  cout << r << "\n";
}
/*
 
*/

Compilation message (stderr)

sparklers.cpp: In function 'long long int sl()':
sparklers.cpp:21:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |   for(int i =1 ; i < a.size() ; i++){
      |                  ~~^~~~~~~~~~
sparklers.cpp:31:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |   for(int i = 1 ;i < b.size() ; i++){
      |                  ~~^~~~~~~~~~
sparklers.cpp:41:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |   for(int i = l ; i < a.size() ; i++){
      |                   ~~^~~~~~~~~~
sparklers.cpp:45:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |   for(int i = l2 ; i < b.size() ; i++){
      |                    ~~^~~~~~~~~~
sparklers.cpp:49:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |   for(int i = l2 ; i < b.size() ; i++){
      |                    ~~^~~~~~~~~~
sparklers.cpp:53:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long double>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |   for(int i = l ; i < a.size() ; i++){
      |                   ~~^~~~~~~~~~
sparklers.cpp:20:15: warning: variable 'sm2' set but not used [-Wunused-but-set-variable]
   20 |   ld sm = 0 , sm2 , val =0  ;int l = 1 ;
      |               ^~~

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