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  1. /*
  2. * @Author: hungeazy
  3. * @Date:   2025-11-17 10:01:08
  4. * @Last Modified by:   hungeazy
  5. * @Last Modified time: 2026-03-14 17:27:48
  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 "THUHOACH"
  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)1e6+10;
  54. int n,k,a[N];
  55.  
  56. namespace sub2 {
  57.  
  58. 	bool approved() {
  59. 		return n <= 5e3;
  60. 	}
  61.  
  62. 	void solve(void)
  63. 	{
  64. 		int ans = 0;
  65. 		FOR(i,1,n)
  66. 		{
  67. 			int sum = 0, gcd = 0;
  68. 			FOR(j,i,n)
  69. 			{
  70. 				sum += a[j];
  71. 				gcd = __gcd(gcd,a[j]);
  72. 				if (j-i+1 >= k) maximize(ans,gcd*sum);
  73. 			}
  74. 		}
  75. 		cout << ans;
  76. 	}
  77.  
  78. }
  79.  
  80. namespace sub4 {
  81.  
  82. 	const int LOG = 21;
  83. 	int pre[N];
  84.  
  85. 	bool approved() {
  86. 		return n <= 5e4;
  87. 	}
  88.  
  89. 	struct RMQ {
  90. 		int rmq[N][LOG],lo[N];
  91.  
  92. 		void init()
  93. 		{
  94. 			FOR(i,1,n) rmq[i][0] = a[i];
  95. 			lo[1] = 0;
  96. 			FOR(i,2,N-10) lo[i] = lo[i/2]+1;
  97. 			FOR(j,1,LOG-1)
  98. 				FOR(i,1,n-MASK(j)+1)
  99. 					rmq[i][j] = __gcd(rmq[i][j-1],rmq[i+MASK(j-1)][j-1]);
  100. 		}
  101.  
  102. 		int getGCD(int l, int r) 
  103. 		{
  104. 			int k = lo[r-l+1];
  105. 			return __gcd(rmq[l][k],rmq[r-MASK(k)+1][k]);
  106. 		}
  107. 	} rmq;
  108.  
  109. 	void solve(void)
  110. 	{
  111. 		FOR(i,1,n) pre[i] = pre[i-1]+a[i];
  112. 		rmq.init();
  113. 		int ans = 0;
  114. 		FOR(i,k,n)
  115. 		{	
  116. 			int gcd = rmq.getGCD(i-k+1,i);
  117. 			maximize(ans,gcd*(pre[i]-pre[i-k]));
  118. 			int L = i-k+1;
  119. 			while (L > 1)
  120. 			{
  121. 				gcd = __gcd(gcd,a[L-1]);
  122. 				int l = 1, r = L-1;
  123. 				while (l <= r)
  124. 				{
  125. 					int mid = (l+r)>>1;
  126. 					if (rmq.getGCD(mid,i) == gcd) L = mid, r = mid-1;
  127. 					else l = mid+1;
  128. 				}
  129. 				maximize(ans,gcd*(pre[i]-pre[L-1]));
  130. 			}
  131. 		}
  132. 		cout << max(ans,pre[n]);
  133. 	}
  134.  
  135. }
  136.  
  137. namespace sub5 {
  138.  
  139. 	int pre[N],nxt[N];
  140.  
  141. 	void solve(void)
  142. 	{
  143. 		FOR(i,1,n) pre[i] = pre[i-1]+a[i];
  144. 		FOR(i,1,n) nxt[i] = i+1;
  145. 		nxt[n+1] = n+1;
  146. 		int ans = 0;
  147. 		FOD(l,n,1)
  148. 		{
  149. 			int now = l;
  150. 			while (now != n+1)
  151. 			{
  152. 				a[now] = __gcd(a[now],a[l]);
  153. 				if (nxt[now]-l >= k)
  154. 					maximize(ans,a[now]*(pre[nxt[now]-1]-pre[l-1]));
  155. 				now = nxt[now];
  156. 			}
  157. 			now = l;
  158. 			while (now != n+1)
  159. 			{
  160. 				if (a[now] == a[nxt[now]]) nxt[now] = nxt[nxt[now]];
  161. 				now = nxt[now];
  162. 			}
  163. 		}
  164. 		cout << ans;
  165. 	}
  166.  
  167. }
  168.  
  169. bool M2;
  170. signed main()
  171. {
  172.     fast;
  173.     if (fopen(name".inp","r"))
  174.     {
  175.     	freopen(name".inp","r",stdin);
  176.     	freopen(name".out","w",stdout);
  177.     }
  178.     cin >> n >> k;
  179.     FOR(i,1,n) cin >> a[i];
  180.     if (sub2::approved()) return sub2::solve(), time(), memory(), 0;
  181.     if (sub4::approved()) return sub4::solve(), time(), memory(), 0;
  182.     sub5::solve();
  183.     time();
  184.     memory();
  185.     return 0;
  186. }
  187. // ██░ ██  █    ██  ███▄    █   ▄████
  188. //▓██░ ██▒ ██  ▓██▒ ██ ▀█   █  ██▒ ▀█▒
  189. //▒██▀▀██░▓██  ▒██░▓██  ▀█ ██▒▒██░▄▄▄░
  190. //░▓█ ░██ ▓▓█  ░██░▓██▒  ▐▌██▒░▓█  ██▓
  191. //░▓█▒░██▓▒▒█████▓ ▒██░   ▓██░░▒▓███▀▒
  192. // ▒ ░░▒░▒░▒▓▒ ▒ ▒ ░ ▒░   ▒ ▒  ░▒   ▒
  193. // ▒ ░▒░ ░░░▒░ ░ ░ ░ ░░   ░ ▒░  ░   ░
  194. // ░  ░░ ░ ░░░ ░ ░    ░   ░ ░ ░ ░   ░
  195. // ░  ░  ░   ░              ░       ░
Success #stdin #stdout #stderr 0.01s 5316KB
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-------------Time:6.42ms.
198.366 MB
https://ideone.com/ELUGPh
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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