Submission #931538

#	Time	Username	Problem	Language	Result	Execution time	Memory
931538		Baizho	Watching (JOI13_watching)	C++14	0 / 100	9 ms	524 KiB

watching

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
  
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
 
// #pragma GCC optimize("Ofast,unroll-loops,fast-math")
// #pragma GCC target("popcnt")
 
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll,ll> pll;
 
#define sz size()
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define pb push_back
 
const int mod = ll(1e9)+7; //(b + (a%b)) % b (to mod -1%(10^9+7) correctly in c++ its -1 but its suppose to be 10^9+6
const ll MOD = 998244353;  // (a%mod)*(binpow(b,mod-2,mod) = (a/b)%mod
const int N = ll(1e5)+100;
const int M = ll(2e5) + 100;
const long long inf = 5e18;
const long double eps = 1e-15L;
 
ll lcm(ll a, ll b) { return (a / __gcd(a,b))*b; }
 
ll binpow(ll a, ll b, ll m) { ll res=1; a %= m; while(b>0){ if(b&1)res=(res * a) % m; a=(a * a) % m; b/=2; } return res%m;}
 
void Freopen(string Key){ freopen((Key+".in").c_str(), "r", stdin); freopen((Key+".out").c_str(), "w", stdout); }
 
int n, p, q, a[N];

int get(int l, int r) {
	return upper_bound(a + 1, a + n + 1, r) - a - (lower_bound(a + 1, a + n + 1, l) - a);
}

bool check(int w, int p, int q) {
//	cout<<w<<" "<<p<<" "<<q<<endl;
	vector<pair<int, int> > vec;
	for(int i = 1; i <= n;) {
		if(p) {
			int next = a[i] + w - 1;
			vec.pb({a[i], a[i] + w - 1});
			p --;
			if(vec.size() >= 2 && q) {
				// switch last two for a 2w photo
				int l1 = vec[vec.size() - 2].ff, r1 = vec[vec.size() - 2].ss;
				// l1 ... next if the same as taking l1...r1, a[i] ... next
//				cout<<i<<" "<<l1<<" "<<r1<<" "<<a	[i]<<" "<<next<<"\n";
				if(get(l1, l1 + 2 * w - 1) == get(l1, r1) + get(a[i], next)) {
//					cout<<i<<" "<<l1<<" "<<r1<<" "<<a	[i]<<" "<<next<<"\n";
					next = l1 + 2 * w - 1;
					// take those two back for the 2w
					p += 2;
					q --;
					vec.pop_back();
					vec.pop_back();
				}
			}
			while(a[i] <= next) i ++;
		} else if(q) {
			// no p left so only choice is to use q at many time as we can
			int next = a[i] + 2 * w - 1;
			q --;
			while(a[i] <= next) i ++;
		} else {
//			cout<<i<<" "<<"\n";
			return false;
		}
	}
	return true;
}
 
void Baizho() {
	cin>>n>>p>>q;
	for(int i = 1; i <= n; i ++) {
		cin>>a[i];
	}
	sort(a + 1, a + n + 1);
//	for(int i = 1; i <= n; i ++) cout<<a[i]<<" ";
//	cout<<endl;
//	int l1, r1; cin>>l1>>r1;
//	cout<<get(l1, r1)<<endl;
	
	int l = 1, r = 1e9;
	while(l <= r) {
		int mid = (l + r) / 2;
		if(check(mid, p, q)) r = mid - 1;
		else l = mid + 1;
	}
	cout<<r + 1<<"\n";
	
	
}
 
signed main() {		
// 	Freopen("nondec");
    ios_base::sync_with_stdio(false);   
    cin.tie(0);cout.tie(0); 
//   	precalc();
   	
    int ttt = 1;
//    cin>>ttt;
 
    for(int i=1; i<=ttt; i++) {Baizho(); }
}

Compilation message (stderr)

watching.cpp: In function 'void Freopen(std::string)':
watching.cpp:35:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 | void Freopen(string Key){ freopen((Key+".in").c_str(), "r", stdin); freopen((Key+".out").c_str(), "w", stdout); }
      |                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:35:76: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 | void Freopen(string Key){ freopen((Key+".in").c_str(), "r", stdin); freopen((Key+".out").c_str(), "w", stdout); }
      |                                                                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 50
• Subtask 2: 0 / 50