Submission #435941

#	Time	Username	Problem	Language	Result	Execution time	Memory
435941		cgiosy	Biochips (IZhO12_biochips)	C++17	0 / 100	5 ms	6476 KiB

biochips

#include <bits/stdc++.h>
using namespace std;

int n,m,inp[200005];
 
int piv,sz[200005],a[200005];
vector<int> g[200005];
int root;
 
int dfs(int x){
    int num = ++piv;
    a[num] = inp[x];
    sz[num] = 1;
    for(int &i : g[x]){
        sz[num] += dfs(i);
    }
    return sz[num];
}
 
int dp[2][200005];
 
void mx(int&a, int b) { a=max(a, b); }
int main() {
	ios::sync_with_stdio(0);cin.tie(0);
	int N, K, r;
	cin>>N>>K;n=N,m=K;
	int D[2][200004], F[N+1], G[N+1]{}, W[N+1];
	for(int i=1; i<=N; i++) {
		int p;
		cin>>p>>W[i];inp[i]=W[i];
		if(p) F[i]=G[p], G[p]=i,g[p].push_back(i);
		else root=r=i;
	}
    dfs(root);
    for (int i=1; i<=m; i++) {
        dp[i%2][n+1] = -1e9;
        for (int j=n; j; j--) {
            dp[i%2][j] = max(dp[i%2][j+1],dp[(i-1)%2][j+sz[j]] + a[j]);
        }
    }
	int n[2]{}, d=0;
	function<int(int)> cg=[&](int i) {
		int p=n[d];
		for(int e=G[i]; e; e=F[e]) {
			d^=1;
			int m=cg(e);
			d^=1;
			int q=n[d^1]-=m, j=min(n[d]-p+m, K);
			while(n[d]<p+j) D[d][n[d]++]=0;
			while(--j) for(int k=min(m, j); k--;)
				mx(D[d][p+j], D[d][p+j-k-1]+D[d^1][q+k]);
			for(int k=0; k<m; k++) mx(D[d][p+k], D[d^1][q+k]);
		}
		if(p==n[d]) D[d][n[d]++]=W[i];
		else mx(D[d][p], W[i]);
		return n[d]-p;
	};
	cout<<(N<=10000 ? dp[m%2][1] : D[0][cg(r)-1])<<'\n';
}

Compilation message (stderr)

biochips.cpp: In function 'int main()':
biochips.cpp:25:12: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   25 |  int N, K, r;
      |            ^

• Subtask 1: 0 / 100