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  1. /*
  2. * @Author: hungeazy
  3. * @Date:   2025-10-22 14:30:13
  4. * @Last Modified by:   hungeazy
  5. * @Last Modified time: 2025-10-23 15:57:16
  6. */
  7. #include <bits/stdc++.h>
  8. #include <ext/pb_ds/assoc_container.hpp> 
  9. #include <ext/pb_ds/tree_policy.hpp> 
  10. // #pragma GCC optimize("O3")  
  11. // #pragma GCC optimize("unroll-loops")  
  12. // #pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")  
  13. using namespace std;
  14. using namespace __gnu_pbds; 
  15. bool M1;
  16. #define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
  17. #define int long long
  18. #define ll long long 
  19. #define ull unsigned long long
  20. #define sz(x) x.size()
  21. #define sqr(x) (1LL * (x) * (x))
  22. #define all(x) x.begin(), x.end()
  23. #define fill(f,x) memset(f,x,sizeof(f))
  24. #define FOR(i,l,r) for(int i=l;i<=r;i++)
  25. #define FOD(i,r,l) for(int i=r;i>=l;i--)
  26. #define debug(x) cout << #x << " = " << x << '\n'
  27. #define ii pair<int,int>
  28. #define iii pair<int,ii>
  29. #define di pair<ii,ii>
  30. #define vi vector<int>
  31. #define vii vector<ii>
  32. #define mii map<int,int>
  33. #define fi first
  34. #define se second
  35. #define pb push_back
  36. #define MOD 1000000007
  37. #define __lcm(a,b) (1ll * ((a) / __gcd((a), (b))) * (b))
  38. #define YES cout << "YES\n"
  39. #define NO cout << "NO\n"
  40. #define MASK(i) (1LL << (i))
  41. #define c_bit(i) __builtin_popcountll(i)
  42. #define BIT(x,i) ((x) & MASK(i))
  43. #define SET_ON(x,i) ((x) | MASK(i))
  44. #define SET_OFF(x,i) ((x) & ~MASK(i))
  45. #define oo 1e18
  46. #define name ""
  47. #define endl '\n'
  48. #define memory() cerr << abs(&M2-&M1)/1024.0/1024 << " MB" << endl
  49. #define time() cerr << endl << "-------------Time:" << 1000.0 * clock() / CLOCKS_PER_SEC << "ms." << endl
  50. template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
  51. template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
  52. template <class T> using ordered_set = tree <T, null_type, less_equal <T>, rb_tree_tag,tree_order_statistics_node_update>;
  53. const int N = (int)1e5+10;
  54. int n,k,a[N];
  55.  
  56. namespace sub1 {
  57.  
  58. 	bool approved() {
  59. 		return n <= 100;
  60. 	}
  61.  
  62. 	void solve(void)
  63. 	{
  64. 		vi ans;
  65. 		for (int len = (k%2 == 0?k+1:k); len <= n; len += 2)
  66. 		{
  67. 			FOR(i,1,n-len+1)
  68. 			{
  69. 				vi vec;
  70. 				FOR(j,i,i+len-1)
  71. 					vec.pb(a[j]);
  72. 				sort(all(vec));
  73. 				ans.pb(vec[len/2]);
  74. 			}
  75. 		}
  76. 		sort(all(ans));
  77. 		ans.erase(unique(all(ans)),ans.end());
  78. 		cout << sz(ans) << endl;
  79. 		for (int x : ans) cout << x << " ";
  80. 	}
  81.  
  82. }
  83.  
  84. namespace sub4 {
  85.  
  86. 	ii b[N];
  87. 	/*
  88. 		Xem những thằng a[i] < x là -1, a[i] > x là +1
  89. 		-> Quy về tìm đoạn con có tổng = 0 và có độ dài >= k và phủ điểm i
  90. 		-> Cố định phần trái <= j -> phần phải >= j+k-1
  91. 		-> Tìm các cặp (a,b) thỏa pre[b]-pre[a-1] = 0
  92. 		   Với a thuộc phần trái, b thuộc phần phải 
  93. 		-> Các thằng giá trị ở đây chỉ là -1/1 -> kiểm tra xem 2 đoạn:
  94. 		[mina,maxa] và [minb,maxb] có giao nhau hay không
  95. 		-> Segment Lazy + Min max.
  96. 	*/
  97. 	struct SegmentTree {
  98. 		int lazy[N<<2];
  99.  
  100. 		struct Node {
  101. 			int mn,mx;
  102. 			Node() {mn = oo; mx = -oo;};
  103. 			Node(int _mn, int _mx):
  104. 				mn(_mn), mx(_mx) {};
  105. 			friend Node operator+(Node L, Node R)
  106. 			{
  107. 				Node res;
  108. 				res.mx = max(L.mx,R.mx);
  109. 				res.mn = min(L.mn,R.mn);
  110. 				return res;
  111. 			}
  112. 		} st[N<<2];
  113.  
  114. 		void down(int id)
  115. 		{
  116. 			if (!lazy[id]) return;
  117. 			int &k = lazy[id];
  118. 			for (int i : {id<<1,id<<1|1})
  119. 			{
  120. 				st[i].mx += k;
  121. 				st[i].mn += k;
  122. 				lazy[i] += k;
  123. 			}
  124. 			k = 0;
  125. 		}
  126.  
  127. 		void updatePos(int id, int l, int r, int pos, int val)
  128. 		{
  129. 			if (l == r)
  130. 			{
  131. 				st[id] = Node(val,val);
  132. 				lazy[id] = 0;
  133. 				return;
  134. 			}
  135. 			int mid = (l+r)>>1; 
  136. 			if (pos <= mid) updatePos(id<<1,l,mid,pos,val);
  137. 			else updatePos(id<<1|1,mid+1,r,pos,val);
  138. 			st[id] = st[id<<1]+st[id<<1|1];
  139. 		}
  140.  
  141. 		void update(int id, int l, int r, int u, int v, int val)
  142. 		{
  143. 			if (l > v or r < u) return;
  144. 			if (l >= u and r <= v)
  145. 			{
  146. 				st[id].mn += val;
  147. 				st[id].mx += val;
  148. 				lazy[id] += val;
  149. 				return;
  150. 			}
  151. 			int mid = (l+r)>>1; down(id);
  152. 			update(id<<1,l,mid,u,v,val);
  153. 			update(id<<1|1,mid+1,r,u,v,val);
  154. 			st[id] = st[id<<1]+st[id<<1|1];
  155. 		}
  156.  
  157. 		Node get(int id, int l, int r, int u, int v)
  158. 		{
  159. 			if (l > v or r < u) return Node();
  160. 			if (l >= u and r <= v) return st[id];
  161. 			int mid = (l+r)>>1; down(id);
  162. 			return get(id<<1,l,mid,u,v)+get(id<<1|1,mid+1,r,u,v);
  163. 		}
  164. 	} IT;
  165.  
  166. 	void solve(void)
  167. 	{
  168. 		if (k%2 == 0) k++;
  169. 		FOR(i,1,n) b[i] = {a[i],i};
  170. 		vi ans;
  171. 		sort(b+1,b+n+1);
  172. 		FOR(i,0,n) IT.updatePos(1,0,n,i,-i);
  173. 		FOR(i,1,n)
  174. 		{
  175. 			int pos = b[i].se;
  176. 			IT.update(1,0,n,pos,n,1);
  177. 			if (ans.empty() or ans.back() != b[i].fi)
  178. 				FOR(j,max(1LL,pos-k+1),pos)
  179. 				{
  180. 					if (j+k-1 > n) break;
  181. 					auto left = IT.get(1,0,n,0,j-1), right = IT.get(1,0,n,j+k-1,n);
  182. 					//pre[j]-pre[i] = 0
  183. 					if ((left.mn <= right.mn and right.mn <= left.mx) or (right.mn <= left.mn and left.mn <= right.mx))
  184. 					{
  185. 						ans.pb(b[i].fi);
  186. 						break;
  187. 					}
  188. 					if (left.mx <= right.mn) j += right.mn-left.mx-1;
  189. 					else j += left.mn-right.mx-1;
  190. 				}
  191. 			IT.update(1,0,n,pos,n,1);
  192. 		}
  193. 		cout << sz(ans) << endl;
  194. 		for (int x : ans) cout << x << " ";
  195. 	}
  196.  
  197. }
  198.  
  199. bool M2;
  200. signed main()
  201. {
  202.     fast;
  203.     if (fopen(name".inp","r"))
  204.     {
  205.     	freopen(name".inp","r",stdin);
  206.     	freopen(name".out","w",stdout);
  207.     }
  208.     cin >> n >> k;
  209.     FOR(i,1,n) cin >> a[i];
  210.     // if (sub1::approved()) return sub1::solve(), time(), memory(), 0;
  211.     sub4::solve();
  212.     time();
  213.     memory();
  214.     return 0;
  215. }
  216. // ██░ ██  █    ██  ███▄    █   ▄████
  217. //▓██░ ██▒ ██  ▓██▒ ██ ▀█   █  ██▒ ▀█▒
  218. //▒██▀▀██░▓██  ▒██░▓██  ▀█ ██▒▒██░▄▄▄░
  219. //░▓█ ░██ ▓▓█  ░██░▓██▒  ▐▌██▒░▓█  ██▓
  220. //░▓█▒░██▓▒▒█████▓ ▒██░   ▓██░░▒▓███▀▒
  221. // ▒ ░░▒░▒░▒▓▒ ▒ ▒ ░ ▒░   ▒ ▒  ░▒   ▒
  222. // ▒ ░▒░ ░░░▒░ ░ ░ ░ ░░   ░ ▒░  ░   ░
  223. // ░  ░░ ░ ░░░ ░ ░    ░   ░ ░ ░ ░   ░
  224. // ░  ░  ░   ░              ░       ░
Success #stdin #stdout #stderr 0.01s 14040KB
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-------------Time:5.827ms.
11.4453 MB
https://ideone.com/lKNG6p
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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