51nod 1412 AVL tree Type (DP)

Topic Links: Types of 51nod 1412 AVL trees

When I started to do it, I turned the depth too small. The result has been WA, I was naïve.

1#include <cstdio>2#include <cstring>3#include <algorithm>4#include <queue>5 using namespacestd;6typedefLong Longll;7 Const intMoD = 1e9+7;8 Const intN =2001;9ll dp[n][ -];//Dp[i][k] I: Number of nodes, K: DepthTen voidsolve () { One     intI, J, K; Adp[0][0] = dp[1][1] =1; -      for(i =2; i < N; ++i) { -          for(k =2; K < -; ++k) { the              for(j =0; J < I; ++j) { -                 //J is the number of nodes in the right subtree, and the sum of the i-1 nodes is -                 //The left and right sub-tree depth same -Dp[i][k] + = dp[i-1-j][k-1] * dp[j][k-1]; +                 //left and right sub-tree depth difference one -Dp[i][k] + =2* dp[i-1-j][k-2] * dp[j][k-1]; +DP[I][K]%=MoD; A             } at         } -     } - } - intMain () { -     intn, I; -ll ans =0; in solve (); -scanf"%d", &n); to      for(i =1; I < -; ++i) { +Ans + =Dp[n][i]; -     } theAns%=MoD; *printf"%lld\n", ans); $     return 0;Panax Notoginseng}

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51nod 1412 AVL tree Type (DP)