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  1. #include <bits/stdc++.h>
  2. typedef long long ll;
  3. using namespace std;
  4. ll T,n,a[110];
  5. ll dp[110][110][110];
  6. ll solve(ll ind,ll x,ll y)
  7. {
  8.     if(ind == n + 1) return 0;
  9.     if(dp[ind][x][y] != -1) return dp[ind][x][y];
  10.     ll ret = solve(ind+1,x,y);
  11.     if(x == 0) ret = max(ret,1 + solve(ind+1,ind,y));     // chose the 1st element  belonging to the increasing seq.
  12.     if(y == 0) ret = max(ret,1 + solve(ind+1,x,ind));     // chose the 1st element  belonging to the decreasing seq.
  13.     if(a[ind] > a[x]) ret = max(ret,1 + solve(ind+1,ind,y));
  14.     if(a[ind] < a[y]) ret = max(ret,1 + solve(ind+1,x,ind));
  15.     return dp[ind][x][y] = ret;
  16.  
  17. }
  18. int main()
  19. {
  20.     cin >> T;
  21.     while(T--)
  22.     {
  23.         memset(dp,-1,sizeof dp);
  24.         cin >> n;
  25.         for(ll i=1;i<=n;i++) cin >> a[i];
  26.         cout << solve(1,0,0) << endl; // here solve(i , j , k) means we are at the ith index
  27.                                         // 'j' means the last index we had chosen that was part of the INCREASING sequence
  28.                                         // 'k' means the last index we had chosen that was part of the DECREASING sequence
  29.                                         // j >= 0 and k >= 0 , but j == 0 means we have not yet chosen the first increasing sequence number
  30.                                         // likewise k == 0 means the same
  31.     }
  32.     return 0;
  33. }
  34.  
Success #stdin #stdout 0s 4448KB
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https://ideone.com/mvdgcq
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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