随笔档案

#include <cstdio>
#include <cstring>
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
const int maxn = 111;
int n,m;
vector<int> G[maxn];
int dp[maxn][maxn];
bool vis[maxn];
int c[maxn],w[maxn];//c means the number of bugs,w beans brains
void dfs(int u) {
    vis[u] = 1;
    int t=(c[u]+19) / 20;
    int sz = G[u].size();
    for(int i=0;i<sz;i++) {
        int v=G[u][i];
        if(vis[v]) continue;
        dfs(v);
        for(int j=m-t;j>=1;j--)
            for(int k=1;k<=j;k++)
                dp[u][j] = max(dp[u][j],dp[u][j-k]+dp[v][k]);   
    }
    for(int i=m;i>=t;i--)
        dp[u][i] = dp[u][i-t] + w[u];
    for(int i=t-1;i>=0;i--)
        dp[u][i] = 0;
}
int main() {
    while(~scanf("%d%d",&n,&m)) {
        if(n < 0) break;
        for(int i=1;i<=n;i++) G[i].clear(),vis[i]=0;
        memset(dp,0,sizeof(dp));
        for(int i=1;i<=n;i++) scanf("%d%d",&c[i],&w[i]);
        for(int i=1;i<n;i++) {
            int u,v;
            scanf("%d%d",&u,&v);
            G[u].push_back(v);
            G[v].push_back(u);   
        }   
        if(m == 0) {
            puts("0");
            continue;   
        }
        dfs(1);
        printf("%d\n",dp[1][m]);
    }
    return 0;   
}