Submission #1029266

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029266		berr	Table Tennis (info1cup20_tabletennis)	C++17	100 / 100	516 ms	5336 KiB

tabletennis

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

void f(){
	#ifndef ONLINE_JUDGE
	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w", stdout);
	#endif
}

signed main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);

//	f();
	srand(time(0));

	int n, k; cin >>n >> k;

	vector<int> a(n+k);

	for(auto &i: a) cin >> i;

	vector<int> vis(n+k);
	int ans=0;
	vector<int> gh;
	auto check=[&](int val, int type){
		int p=n+k-1;
		int all=0;
		for(int i=0; i<p&&i<n+k&&all<n/2; i++){
			while(p>0&&a[i]+a[p]>val) p--;
			if(i<p&&a[i]+a[p]==val){
				all++;
				if(type){
					gh.push_back(a[i]);
					gh.push_back(a[p]);
				}
			}
		}
		if(all==n/2) return 1;
		return 0;
	};

	if(k<20){
		for(int i=0; i<=20&&i<n+k&&ans==0; i++){
			for(int j=0; j<=20&&j<n+k-1&&ans==0; j++){
				if(check(a[i]+a[n+k-j-1], 0)){
					ans=a[i]+a[n+k-j-1];				
				}
			}
		}
	}
	while(ans==0){
		int val=rand()%(3*k);
		if(vis[val]) continue;
		int j=k+val;
		vis[val]=1;
		for(int l=0; l<=j; l++){

			if( check(a[val]+a[n+k-l-1], 0)){
				ans=a[val]+a[n+k-l-1];
			}
		}
	}

	check(ans, 1);
	sort(gh.begin(), gh.end());

	for(auto i: gh) cout<<i<<" ";

}

Compilation message (stderr)

tabletennis.cpp: In function 'void f()':
tabletennis.cpp:6:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    6 |  freopen("in.txt", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
tabletennis.cpp:7:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |  freopen("out.txt", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 9 / 9
• Subtask 3: 14 / 14
• Subtask 4: 15 / 15
• Subtask 5: 9 / 9
• Subtask 6: 14 / 14
• Subtask 7: 15 / 15
• Subtask 8: 13 / 13