Submission #913966

#	Time	Username	Problem	Language	Result	Execution time	Memory
913966		trashaccount	Biochips (IZhO12_biochips)	C++17	90 / 100	333 ms	404564 KiB

biochips

#include <bits/stdc++.h>
using namespace std;
 
const int NM = 2e5, MM = 500, inf = 1e9+7;
 
int N, M, root = 1, p[NM+5], x[NM+5], timer = 0, tin[NM+5], tout[NM+5], tour[NM+5];
vector <int> son[NM+5];
int dp[NM+5][MM+5], ans = -inf;
 
void dfs_euler_tour(int u){
	tin[u] = ++timer;
	tour[timer] = u;
	for (int v : son[u]){
		dfs_euler_tour(v);
	}
	tout[u] = timer;
}
 
int main(){
//	freopen("BIOCHIPS.inp", "r", stdin);
//	freopen("BIOCHIPS.out", "w", stdout);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin >> N >> M;
	for (int i = 1; i <= N; i++){
		cin >> p[i] >> x[i];
		if (p[i] == 0) root = i;
		son[p[i]].push_back(i);
	}
	dfs_euler_tour(root);
	for (int i = 0; i <= N+1; i++)
		for (int j = 0; j <= M; j++)
			dp[i][j] = -inf;
	dp[N+1][0] = 0;
	for (int i = N; i >= 1; i--){
		int u = tour[i];
		dp[i][0] = 0;
		for (int j = 1; j <= M; j++){
			dp[i][j] = dp[tout[u]+1][j-1]+x[u];
			dp[i][j] = max(dp[i][j], dp[i+1][j]);
		}
		ans = max(ans, dp[i][M]);
	}
	cout << ans;
	return 0;
}

• Subtask 1: 90 / 100