HDU 1011（树形dp）

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<algorithm>
#include<iostream>
using namespace std;

int dp[105][105];
int cost[105];
int value[105];
vector<int> list[105];
int N, M;
bool visited[105];

void dfs(int father)
{
int temp = (cost[father] + 19) / 20;
int len = list[father].size();
for (int i = temp; i <= M; i++)
dp[father][i] = value[father];
visited[father] = true;
for (int i = 0; i <len; i++)
{
int child = list[father][i];
if (visited[child])
continue;
dfs(child);
for (int j = M; j >= temp; j--)
{
for (int k = 1; k <= j - temp; k++)
{
dp[father][j] = max(dp[father][j], dp[father][j - k] + dp[child][k]);
}

}

}
}
int main()
{
while (scanf("%d%d", &N, &M))
{
for (int i = 0; i <= N; i++)
{
list[i].clear();
}
if (N == -1 && M == -1)
return 0;
memset(dp, 0, sizeof(dp));
memset(value, 0, sizeof(value));
memset(cost, 0, sizeof(cost));
memset(visited, false, sizeof(visited));
for (int i = 1; i <= N; i++)
{
cin >> cost[i] >> value[i];
}
int a, b;
for (int i = 1; i <= N - 1; i++)
{
cin >> a >> b;
list[b].push_back(a);
list[a].push_back(b);
}
if (M == 0) { printf("0\n"); continue; }
dfs(1);
cout << dp[1][M] << endl;
}
return 0;
}