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  1. /*
  2. * @Author: hungeazy
  3. * @Date:   2025-11-23 00:40:27
  4. * @Last Modified by:   hungeazy
  5. * @Last Modified time: 2025-11-23 21:56:49
  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 "CIRCLE"
  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)2e3+10;
  54. int n,k,a[N];
  55.  
  56. namespace hungeazy {
  57.  
  58. 	int dp[N][N/3][3];
  59. 	/*
  60. 		dp[i][j][0/1/2]: số điểm lớn nhất đạt được khi xét tới phần tử thứ i,
  61. 		j nhóm và phần tử thứ i là vị trí 0/1/2 trong nhóm
  62. 	*/
  63. 	void solve(void)
  64. 	{
  65. 		int ans = -oo;
  66. 		FOR(i,1,n)
  67. 		{
  68. 			int realPos = (i-1)%n;
  69. 			dp[i][1][0] = dp[i][1][2] = a[realPos];
  70. 			dp[i][1][1] = -a[realPos]; 
  71. 			FOR(j,2,k)
  72. 			{
  73. 				dp[i][j][1] = max(dp[i-1][j][1],dp[i-1][j][0]-a[realPos]);
  74. 				dp[i][j][2] = max(dp[i-1][j][2],dp[i-1][j][1]+a[realPos]);
  75. 				dp[i][j][0] = dp[i-1][j][0];
  76. 				if (j >= 2) maximize(dp[i][j][0],dp[i-1][j-1][2]+a[realPos]);
  77. 			}
  78. 			maximize(ans,max({dp[i][k][0],dp[i][k][1],dp[i][k][2]}));
  79. 		}
  80. 		cout << ans;
  81. 	}
  82.  
  83. }
  84.  
  85. bool M2;
  86. signed main()
  87. {
  88.     fast;
  89.     if (fopen(name".inp","r"))
  90.     {
  91.     	freopen(name".inp","r",stdin);
  92.     	freopen(name".out","w",stdout);
  93.     }
  94.     cin >> n >> k;
  95.     FOR(i,0,n-1) cin >> a[i];
  96.     hungeazy::solve();
  97.     time();
  98.     memory();
  99.     return 0;
  100. }
  101. // ██░ ██  █    ██  ███▄    █   ▄████
  102. //▓██░ ██▒ ██  ▓██▒ ██ ▀█   █  ██▒ ▀█▒
  103. //▒██▀▀██░▓██  ▒██░▓██  ▀█ ██▒▒██░▄▄▄░
  104. //░▓█ ░██ ▓▓█  ░██░▓██▒  ▐▌██▒░▓█  ██▓
  105. //░▓█▒░██▓▒▒█████▓ ▒██░   ▓██░░▒▓███▀▒
  106. // ▒ ░░▒░▒░▒▓▒ ▒ ▒ ░ ▒░   ▒ ▒  ░▒   ▒
  107. // ▒ ░▒░ ░░░▒░ ░ ░ ░ ░░   ░ ▒░  ░   ░
  108. // ░  ░░ ░ ░░░ ░ ░    ░   ░ ░ ░ ░   ░
  109. // ░  ░  ░   ░              ░       ░
Success #stdin #stdout #stderr 0.01s 5320KB
comments (?)
stdin 
Standard input is empty
stdout 
-1000000000000000000
stderr 
-------------Time:4.735ms.
30.8389 MB
https://ideone.com/4JcJC8
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

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