HDU 1561 The more, The Better

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

const int maxn = 200 + 10;
int n, m;
int val[maxn];
int dp[maxn][maxn];
int flag[maxn], tmp[maxn];
int w[maxn*maxn], c[maxn*maxn];
int u;
vector<int>tree[maxn];

void init()
{
memset(dp, -1, sizeof dp);
memset(val, 0, sizeof val);
for (int i = 0; i <= n; i++) dp[i][0] = 0;
for (int i = 0; i <= n; i++) tree[i].clear();
}

void read()
{
for (int i = 1; i <= n; i++)
{
int a, b;
scanf("%d%d", &a, &b);
val[i] = b;
tree[a].push_back(i);
}
}

void dfs(int now)
{
if (!tree[now].size())
{
dp[now][1] = val[now];
return;
}

for (int i = 0; i<tree[now].size(); i++)
dfs(tree[now][i]);

memset(flag, -1, sizeof flag);
flag[0] = 0;

if (now != 0)
{
for (int i = 0; i<tree[now].size(); i++)
{
u = 0;
for (int j = 1; j <= m; j++)
if (dp[tree[now][i]][j] != -1)
w[u] = dp[tree[now][i]][j], c[u++] = j;

memset(tmp, -1, sizeof tmp);
for (int k = 0; k<u; k++)
for (int j = m - 1; j >= c[k]; j--)
if (flag[j - c[k]] != -1)
if (flag[j - c[k]] + w[k]>flag[j] && flag[j - c[k]] + w[k]>tmp[j])
tmp[j] = flag[j - c[k]] + w[k];

for (int j = 1; j <= m - 1; j++) if (tmp[j]>flag[j]) flag[j] = tmp[j];
}
for (int i = 1; i <= m; i++) if (flag[i - 1] != -1) dp[now][i] = flag[i - 1] + val[now];
}

else
{
for (int i = 0; i<tree[now].size(); i++)
{
u = 0;
for (int j = 1; j <= m; j++)
if (dp[tree[now][i]][j] != -1)
w[u] = dp[tree[now][i]][j], c[u++] = j;

memset(tmp, -1, sizeof tmp);
for (int k = 0; k<u; k++)
for (int j = m; j >= c[k]; j--)
if (flag[j - c[k]] != -1)
if (flag[j - c[k]] + w[k]>flag[j] && flag[j - c[k]] + w[k]>tmp[j])
tmp[j] = flag[j - c[k]] + w[k];

for (int j = 1; j <= m; j++) if (tmp[j]>flag[j]) flag[j] = tmp[j];
}
for (int i = 1; i <= m; i++)  dp[now][i] = flag[i];
}
}

void work()
{
dfs(0);
printf("%d\n", dp[0][m]);
}

int main()
{
while (~scanf("%d%d", &n, &m))
{
if (!n&&!m) break;
init();
read();
work();
}
return 0;
}