94 lines
1.9 KiB
C++
94 lines
1.9 KiB
C++
#include<iostream>
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#include<sstream>
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#include<fstream>
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#include<vector>
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#include<list>
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#include<deque>
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#include<queue>
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#include<stack>
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#include<map>
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#include<set>
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#include<bitset>
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#include<algorithm>
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#include<cstdio>
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#include<cstdlib>
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#include<cstring>
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#include<cctype>
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#include<cmath>
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#include<ctime>
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#include<iomanip>
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using namespace std;
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const double eps(1e-8);
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typedef long long lint;
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#define maxn 100010
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int N, K, root;
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int w[maxn];
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bool select[maxn];
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vector<int> G[maxn];
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int f[maxn];
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void dfs(int now)
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{
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int nex;
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int mx = -1e9;
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for(int i = 0, sz = G[now].size(); i < sz; i++)
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{
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nex = G[now][i];
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dfs(G[now][i]);
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f[now] = max(f[now], max(f[nex], w[nex] + mx));
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w[now] = max(w[now], w[nex]);
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mx = max(mx, w[nex]);
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}
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return;
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}
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void solve()
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{
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memset(select, 0, sizeof(select));
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priority_queue<pair<int, int> > Q;
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Q.push(make_pair(w[root], root));
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int ret = 0;
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while(K)
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{
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if(Q.empty())
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{
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puts("0");
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return;
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}
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int u = Q.top().second;
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Q.pop();
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if(select[u])
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{
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K++;
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select[u] = 0;
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ret -= w[u];
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for(int i = 0, sz = G[u].size(); i < sz; i++) Q.push(make_pair(w[G[u][i]], G[u][i]));
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}
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else
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{
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K--;
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select[u] = 1;
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ret += w[u];
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Q.push(make_pair(f[u] - w[u], u));
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}
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}
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printf("%d\n", ret);
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return;
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}
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int main()
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{
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while(scanf("%d %d", &N, &K), N || K)
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{
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for(int i = 1; i <= N; i++) G[i].clear();
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int p;
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for(int i = 1; i <= N; i++)
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{
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f[i] = -1e9;
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scanf("%d %d", &p, w + i);
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if(p == 0) root = i;
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else G[p].push_back(i);
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}
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dfs(root);
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solve();
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}
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return 0;
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}
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