#include <iostream>
#include <vector>
#include <cstring>
#include <cstdio>
using namespace std;
const int maxn = 110;
int n, m;
int cos[maxn], weg[maxn];
int dp[maxn][maxn];
bool vis[maxn];
vector<int> tree[maxn];//建树
inline int max(int a, int b) {
return a > b ? a : b;
}
void dfs(int p) {
int i, j, k;
int temp = (cos[p] + 19)/20;//攻打p至少需要temp个人
for(i = temp; i <= m; i++)
dp[p][i] = weg[p];
vis[p] = 1;//记录下已经处理p节点,强制只能顺着树往下撸
for(i = 0; i < tree[p].size(); i++) {
int t = tree[p][i];
if(vis[t])
continue;
dfs(t);
for(j = m; j >= temp; j--) {//树形背包,容量从后向前推
for(k = 1; k <= j-temp; k++)//留下j-k攻打p,k攻打儿子
dp[p][j] = max(dp[p][j], dp[p][j-k] + dp[t][k]);
}
}
}
int main() {
freopen("data.in", "r", stdin);
int i;
while(scanf("%d%d", &n, &m), n != -1 || m != -1) {
for(i = 0; i <= n; i++)
tree[i].clear();
memset(dp, 0, sizeof(dp));
memset(vis, 0, sizeof(vis));
for(i = 1; i <= n; i++)
scanf("%d%d", cos+i, weg+i);
for(i = 1; i < n; i++) {
int u, v;
scanf("%d%d", &u, &v);
tree[u].push_back(v);
tree[v].push_back(u);
}
if(m == 0) {
printf("0\n");
continue;
}
dfs(1);
printf("%d\n", dp[1][m]);
}
return 0;
}
HDU 1011 Starship Troopers(树形背包)
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转载自blog.csdn.net/ccshijtgc/article/details/81215385
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