Submission #1065428

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065428		_rain_	Jobs (BOI24_jobs)	C++14	0 / 100	2065 ms	25504 KiB

Main

#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
#define debug false
#define int long long

const int maxn = 3e5;
vector<int> graph[maxn+2];
int x[maxn+2] , p[maxn+2];
bool root[maxn+2];
int n;
i64 s , pre[maxn+2] , f[maxn+2] , dp[maxn+2];
i64 dfs(int u , int p , i64 sum){
	sum += x[u];
	if (sum < 0) return sum;
	for (auto& v : graph[u]){
		if (v!=p){
			sum = max(sum , dfs(v,u,sum));
		}
	}
	if (debug){
		cout << "( DEBUG )\n";
		cout << u << ' ' << sum << '\n';
	}
	return sum;
}

signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	
	cin >> n >> s;	
	bool ok = true;
	for (int i = 1; i <= n; ++i){
		cin >> x[i] >> p[i];
		if (p[i] != 0 && p[i] != i - 1) ok = false;
		if (p[i]==0) root[i] = true;
			else graph[p[i]].push_back(i);
	}
	i64 alter = s;
	for (int i = 1; i <= n; ++i){
		if (root[i])
			s = max(s , dfs(i,i,s));
	}
	if (ok){
		cout << s - alter;
		return 0;
	}
	
	for (int i = 1; i <= n; ++i) pre[i] = pre[i - 1] + x[i];
	f[0] = s;
	for (int i = 1; i <= n; ++i){
		int pos = i;
		for (int j = i; j >= 1; --j){
			dp[i] = max(dp[i] , dp[j]);
			if (p[j]==0){
				pos = j; break;
			}	
		}
		dp[i] = max(dp[i] , f[pos - 1] + pre[i] - pre[pos - 1]);
		dp[i] = max(dp[i] , f[pos - 1]);
		f[i] = max(dp[i] , f[i - 1]);
	}
	cout << dp[n] - s;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 29
• Subtask 5: 0 / 31