AcWing 10. 有依赖的背包问题
原题链接
困难
作者:
zhuqingyun
,
2024-03-01 21:36:35
,
所有人可见
,
阅读 20
#include <bits/stdc++.h>
using namespace std;
const int N = 110;
int n, m;
int v[N], w[N];
int h[N], e[N], ne[N], idx;
int f[N][N];
void add(int a, int b)
{
e[idx] = b, ne[idx] = h[a], h[a] = idx ++ ;
}
void dfs(int u)
{
for (int i = h[u]; i != -1; i = ne[i]) //i != -1也可以写成~i。见https://blog.csdn.net/weixin_44751167/article/details/119519451
{
int son = e[i];
dfs(e[i]);
for (int j = m - v[u]; j >= 0; j -- )
for (int k = 0; k <= j; k ++ )
f[u][j] = max(f[u][j], f[u][j - k] + f[son][k]);
}
for (int i = m; i >= v[u]; i -- ) f[u][i] = f[u][i - v[u]] + w[u];
for (int i = 0; i < v[u]; i ++ ) f[u][i] = 0;
}
int main()
{
scanf("%d%d", &n, &m);
memset(h, -1, sizeof h);
int root;
for (int i = 1; i <= n; i ++ )
{
int p;
scanf("%d%d%d", &v[i], &w[i], &p);
if (p == -1) root = i;
else add(p, i);
}
dfs(root);
printf("%d\n", f[root][m]);
return 0;
}