[HDOJ1561]The more, The Better（树dp，背包）

  1 /*
  2 ━━━━━┒ギリギリ♂ eye！
  3 ┓┏┓┏┓┃キリキリ♂ mind！
  4 ┛┗┛┗┛┃＼○／
  5 ┓┏┓┏┓┃ /
  6 ┛┗┛┗┛┃ノ)
  7 ┓┏┓┏┓┃
  8 ┛┗┛┗┛┃
  9 ┓┏┓┏┓┃
 10 ┛┗┛┗┛┃
 11 ┓┏┓┏┓┃
 12 ┛┗┛┗┛┃
 13 ┓┏┓┏┓┃
 14 ┃┃┃┃┃┃
 15 ┻┻┻┻┻┻
 16 */
 17 #include <algorithm>
 18 #include <iostream>
 19 #include <iomanip>
 20 #include <cstring>
 21 #include <climits>
 22 #include <complex>
 23 #include <fstream>
 24 #include <cassert>
 25 #include <cstdio>
 26 #include <bitset>
 27 #include <vector>
 28 #include <deque>
 29 #include <queue>
 30 #include <stack>
 31 #include <ctime>
 32 #include <set>
 33 #include <map>
 34 #include <cmath>
 35 using namespace std;
 36 #define fr first
 37 #define sc second
 38 #define cl clear
 39 #define BUG puts("here!!!")
 40 #define W(a) while(a--)
 41 #define pb(a) push_back(a)
 42 #define Rint(a) scanf("%d", &a)
 43 #define Rs(a) scanf("%s", a)
 44 #define Cin(a) cin >> a
 45 #define FRead() freopen("in", "r", stdin)
 46 #define FWrite() freopen("out", "w", stdout)
 47 #define Rep(i, len) for(int i = 0; i < (len); i++)
 48 #define For(i, a, len) for(int i = (a); i < (len); i++)
 49 #define Cls(a) memset((a), 0, sizeof(a))
 50 #define Clr(a, x) memset((a), (x), sizeof(a))
 51 #define Full(a) memset((a), 0x7f7f7f, sizeof(a))
 52 #define lrt rt << 1
 53 #define rrt rt << 1 | 1
 54 #define pi 3.14159265359
 55 #define RT return
 56 #define lowbit(x) x & (-x)
 57 #define onecnt(x) __builtin_popcount(x)
 58 typedef long long LL;
 59 typedef long double LD;
 60 typedef unsigned long long ULL;
 61 typedef pair<int, int> pii;
 62 typedef pair<string, int> psi;
 63 typedef pair<LL, LL> pll;
 64 typedef map<string, int> msi;
 65 typedef vector<int> vi;
 66 typedef vector<LL> vl;
 67 typedef vector<vl> vvl;
 68 typedef vector<bool> vb;
 69 
 70 const int maxn = 220;
 71 vi G[maxn];
 72 int n, m;
 73 int w[maxn];
 74 bool vis[maxn];
 75 int dp[maxn][maxn];
 76 
 77 void dfs(int u) {
 78     For(i, 1, m+1) dp[u][i] = w[u];
 79     vis[u] = 1;
 80     Rep(i, G[u].size()) {
 81         int v = G[u][i];
 82         if(vis[v]) continue;
 83         dfs(v);
 84         if(u == 0) {
 85             for(int j = m; j >= 0; j--) {
 86                 for(int k = j; k >= 0; k--) {
 87                     dp[u][j] = max(dp[u][j], dp[u][k]+dp[v][j-k]);
 88                 }
 89             }
 90         }
 91         else {
 92             for(int j = m; j >= 0; j--) {
 93                 for(int k = j - 1; k >= 1; k--) {
 94                     dp[u][j] = max(dp[u][j], dp[u][k]+dp[v][j-k]);
 95                 }
 96             }
 97         }
 98     }
 99 }
100 
101 int main() {
102     // FRead();
103     int a, b;
104     while(~Rint(n) && ~Rint(m) && n + m) {
105         Rep(i, n+5) G[i].clear();
106         Cls(dp); Cls(vis);
107         For(i, 1, n+1) {
108             Rint(a); Rint(b);
109             G[a].push_back(i);
110             w[i] = b;
111         }
112         dfs(0);
113         printf("%d\n", dp[0][m]);
114     }
115     RT 0;
116 }