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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define Foreach(i, c) for(__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
  4. #define For(i,a,b) for(int (i)=(a);(i) < (b); ++(i))
  5. #define rof(i,a,b) for(int (i)=(a);(i) > (b); --(i))
  6. #define rep(i, c)  for(auto &(i) : (c))
  7. #define x     first
  8. #define y     second
  9. #define pb  push_back
  10. #define PB  pop_back()
  11. #define iOS  ios_base::sync_with_stdio(false)
  12. #define sqr(a)  (((a) * (a)))
  13. #define all(a)  a.begin() , a.end()
  14. #define error(x) cerr << #x << " = " << (x) <<endl
  15. #define Error(a,b) cerr<<"( "<<#a<<" , "<<#b<<" ) = ( "<<(a)<<" , "<<(b)<<" )\n";
  16. #define errop(a) cerr<<#a<<" = ( "<<((a).x)<<" , "<<((a).y)<<" )\n";
  17. #define coud(a,b) cout<<fixed << setprecision((b)) << (a)
  18. #define L(x)  ((x)<<1)
  19. #define R(x)  (((x)<<1)+1)
  20. #define umap  unordered_map
  21. //#define max(x,y)  ((x) > (y) ? (x) : (y))
  22. //#define double long double
  23. typedef long long ll;
  24. #define int ll
  25. typedef pair<ll,ll>pii;
  26. typedef vector<int> vi;
  27. //typedef complex<double> point;
  28. const int maxn = 1e6 + 100;
  29. map <pii, vi> mp;
  30. struct point{
  31. 	ll x,y;
  32. 	point(){
  33. 	 	x = y = 0;
  34. 	}
  35. 	point(ll a,ll b){
  36. 		x = a, y = b;
  37. 	}
  38. 	inline void init(ll a,ll b){
  39. 		x = a, y = b;
  40. 	}
  41. 	inline point operator - (point p){
  42. 		return point(x - p.x, y - p.y);
  43. 	}
  44. 	inline ll dis(point p){
  45. 		return sqr(x - p.x) + sqr(y - p.y);
  46. 	}
  47. 	inline pii PII(){
  48. 		return pii(x, y);
  49. 	}
  50. };
  51. inline ll CROSS(point o, point a,point b){
  52. 	return (a.y * b.x * o.x * o.y - a.y * o.x * b.x * b.y - o.y * b.x * a.x * a.y + a.x * b.x * a.y * b.y) - 
  53. 		(a.x * b.y * o.x * o.y - a.x * o.y * b.x * b.y - o.x * b.y * a.x * a.y + a.x * b.x * a.y * b.y);
  54. }
  55. point o;
  56. point l;
  57. inline bool ocmp(const point &a, const point &b){
  58. 	return make_pair(a.y, a.x) > make_pair(b.y, b.x);
  59. }
  60. inline bool lcmp(const point &a, const point &b){
  61. 	return make_pair(a.x, a.y) > make_pair(b.x, b.y);
  62. }
  63. inline bool scmp(const point &a,const point &b){
  64. 	ll cross = CROSS(o, a, b);
  65. 	if(!cross)
  66. 		return o.dis(a) < o.dis(b);
  67. 	return cross < 0;
  68. }
  69. vector<point> v;
  70. vector<point> hull;
  71. int n;
  72. main(){
  73.     iOS;
  74. 	cin >> n;
  75. 	For(i,0,n){
  76. 		int a,b;
  77. 		cin >> a >> b;
  78. 		mp[{a, b}].pb(i + 1);
  79. 	}
  80. 	if(mp.size() == 1){
  81. 		For(i,1,n+1)
  82. 			cout << i << ' ';
  83. 		cout << endl;
  84. 		return 0;
  85. 	}
  86. 	Foreach(q, mp){
  87. 		pii p = q->x;
  88. 		int x = p.x, y = p.y;
  89. 		point P;
  90. 		P.init(x, y);
  91. 		v.pb(P);
  92. 	}
  93. 	o = *min_element(all(v), ocmp);
  94. 	l = *min_element(all(v), lcmp);
  95. 	if(o.PII() == l.PII()){
  96. 		rep(a, mp[o.PII()])
  97. 			cout << a << ' ';
  98. 		cout << endl;
  99. 		return 0;
  100. 	}
  101. 	sort(all(v), scmp);
  102. 	int po = 2;
  103. 	For(i,0,2)
  104. 		hull.pb(v[i]);
  105. 	vi ans;
  106. 	while(po < v.size() && hull.back().PII() != l.PII()){
  107. 		while(hull.size() > 1 && CROSS(hull[hull.size()-2], hull[hull.size()-1], v[po]) > 0LL)
  108. 			hull.PB;
  109. 		hull.pb(v[po++]);
  110. 	}
  111. 	rep(p, hull)
  112. 		rep(a, mp[p.PII()])
  113. 			ans.pb(a);
  114. 	sort(all(ans));
  115. 	rep(a, ans)
  116. 		cout << a << ' ';
  117. 	cout << endl;
  118.  
  119. }
  120.  
Runtime error #stdin #stdout 0s 3244KB
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https://ideone.com/ccMHza
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
secret

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