Submission #172309

#	Time	Username	Problem	Language	Result	Execution time	Memory
172309		eggag32	Circle selection (APIO18_circle_selection)	C++17	7 / 100	643 ms	42264 KiB

circle_selection

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define debug(x) cerr << #x << ": " << x << endl;
#define debug2(x, y) debug(x) debug(y);
#define repn(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(i, a) for(int i = 0; i < (int)(a); i++)
#define all(v) v.begin(), v.end() 
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define sq(x) ((x) * (x))

template<class T> T gcd(T a, T b){ return ((b == 0) ? a : gcd(b, a % b)); }

bool cmp(pair<pair<ld, int>, pair<ld, ld>> a, pair<pair<ld, int>, pair<ld, ld>> b){
	if(a.fi.fi != b.fi.fi) return (a.fi.fi > b.fi.fi);
	return (a.fi.se < b.fi.se);
}

bool cmp1(pair<pair<ld, int>, pair<ld, ld>> a, pair<pair<ld, int>, pair<ld, ld>> b){
	return (a.fi.fi < b.fi.fi);
}

bool cmp2(pair<pair<ld, int>, pair<ld, ld>> a, pair<pair<ld, int>, pair<ld, ld>> b){
	return (a.fi.se < b.fi.se);
}

ld dist(ld x, ld y, ld x1, ld y1){
	return sqrtl(sq(x1 - x) + sq(y1 - y));
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	//freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
	int n;
	cin >> n;
	vector<pair<pair<ld, int>, pair<ld, ld>>> c(n);
	int yis0 = 1;
	rep(i, n){
		cin >> c[i].se.fi >> c[i].se.se >> c[i].fi.fi;
		if(c[i].se.se != 0) yis0 = 0;
		c[i].fi.se = i;
	}
	sort(all(c), cmp);
	if(n <= 5000){
		vi vis(n, 0);
		vi ans(n, 0);
		//they are sorted in the way they appear
		rep(i, n) if(!vis[i]){
			repn(j, i + 1, n) if(!vis[j]){
				if(dist(c[i].se.fi, c[i].se.se, c[j].se.fi, c[j].se.se) <= (c[i].fi.fi + c[j].fi.fi)){
					//they intersect
					vis[j] = 1;
					ans[c[j].fi.se] = c[i].fi.se;
				}
			}
			vis[i] = 1;
			ans[c[i].fi.se] = c[i].fi.se;
		}
		rep(i, n) cout << ans[i] + 1 << " ";
		cout << endl;
		return 0;
	}
	/*
	else if(yis0){
		//well, I only got as far as so as putting all endpoints in a vector, so
		//not that far, but I got something
	}
	*/
	else{
		//sort them by y and by x, for each circle, when you find
		//some other circle it intersects, they are both deleted by the
		//one with the larger r[i], or minimum i in case of a tie
		vector<pair<pair<ld, int>, pair<ld, ld>>> c1 = c;
		sort(all(c1), cmp1); //sort by x
		vi vis(n, 0);
		vi ans(n, -1);
		rep(i, c1.size() - 1){
				if(dist(c1[i].se.fi, c1[i].se.se, c1[i + 1].se.fi, c1[i + 1].se.se) <= (c1[i].fi.fi + c1[i + 1].fi.fi)){
					int best = i;
					if(c1[i].fi.fi < c1[i + 1].fi.fi) best = i + 1;
					else if(c1[i].fi.fi == c1[i + 1].fi.fi){
						if(c1[i].fi.se > c1[i + 1].fi.se) best = i + 1;
					}
					ans[c1[i].fi.se] = best;
					ans[c1[i + 1].fi.se] = best;
				}
		}
		c1 = c;
		sort(all(c1), cmp1); //sort by y
		rep(i, c1.size() - 1){
				if(dist(c1[i].se.fi, c1[i].se.se, c1[i + 1].se.fi, c1[i + 1].se.se) <= (c1[i].fi.fi + c1[i + 1].fi.fi)){
					int best = i;
					if(c1[i].fi.fi < c1[i + 1].fi.fi) best = i + 1;
					else if(c1[i].fi.fi == c1[i + 1].fi.fi){
						if(c1[i].fi.se > c1[i + 1].fi.se) best = i + 1;
					}
					ans[c1[i].fi.se] = best;
					ans[c1[i + 1].fi.se] = best;
				}
		}
		rep(i, ans.size()){
			if(ans[i] == -1) ans[i] = i;
			cout << ans[i] + 1 << " ";
		}
		cout << endl;
	}
	return 0;
}
/*
Things to look out for:
	- Integer overflows
	- Array bounds
	- Special cases
Be careful!
*/

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:49:6: warning: variable 'yis0' set but not used [-Wunused-but-set-variable]
  int yis0 = 1;
      ^~~~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13