URAL-1018 Binary Apple Tree---treeview dp

Topic Links:

https://cn.vjudge.net/problem/URAL-1018

Main topic:

Give you a tree, each side has a side right, to 1 as the root node, Q bar side of the number of children (q+1 points), edge weights and maximum.

Problem Solving Ideas:

DP[ROOT][J], which represents the root node, preserving the maximum edge and the J nodes.

Dp[root][j]=max (Dp[root][j],dp[root][j-t]+dp[son][t]+len);

T ranges from 1 to j-1, since each point is updated from dp[][1]

1#include <bits/stdc++.h>2 using namespacestd;3 Const intMAXN = -+Ten;4typedefLong Longll;5 structnode6 {7     intV, W;8 node () {}9NodeintVintW): V (v), W (w) {}Ten }; OneVector<node>MAP[MAXN]; A intNUM[MAXN];//Num[i] Indicates the number of points in a subtree with the I node as root - intDP[MAXN][MAXN];//Dp[i][j] indicates that only J-edge maximum weights are in subtrees with the I node as root - voidDfsintRootintFA) the { -Num[root] =1; -      for(inti =0; I < map[root].size (); i++) -     { +         intv = map[root][i].v, w =MAP[ROOT][I].W; -         if(v = = FA)Continue;//No backtracking +Dfs (v, root);//Update your son's information first. ANum[root] + = Num[v];//current number of nodes in root subtree at          for(intj = Num[root]; J >=1; j--)//update the DP of the parent node -         { -              for(intK =1; K < J && K <= Num[v]; k++)//K cannot be equal to j,k=j when the number of root points is 0 -DP[ROOT][J] = max (Dp[root][j], dp[root][j-k] + dp[v][k] +W); -         } -     } in } - intMain () to { +     intN, K; -      while(SCANF ("%d%d", &n, &k)! =EOF) the     { *Memset (DP,0,sizeof(DP)); $          for(inti =1; I < n; i++)Panax Notoginseng         { -             intu, V, W; thescanf"%d%d%d", &u, &v, &W); + map[u].push_back (Node (v, W)); A Map[v].push_back (Node (u, W)); the         } +Dfs1, -1); -cout<<dp[1][k +1]<<endl;//contains K-bars, or k+1 points $     } $     return 0; -}

URAL-1018 Binary Apple Tree---treeview dp