Submission #1270871

#	Time	Username	Problem	Language	Result	Execution time	Memory
1270871		thdh__	File Paths (BOI15_fil)	C++20	100 / 100	292 ms	40188 KiB

fil

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll

using namespace std;
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());

/*
Competitive Programming notes that I need to study & fix my dumbass self:

1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you

2. Stress: 
- Always try generating big testcases and try if they run

3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time

Time management schedule:
Offline / LAH days (4 problems - 3h):
15' thinking of solution / idea
1. no idea: skip
2. yes idea: continue thinking for <= 15'

+ implementing: <= 20'
+ brute-force: <= 5'
+ test generator: <= 5'

I hate offline because I am dumb
*/

typedef pair<int, int> ii;
const int N = 1e5+5;
const int B = 750;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 

int n,m,k,s;
vector<ii> adj[N];
int h[N], tin[N], tout[N], timer = 0, par[N];
unordered_map<int, int> mp;
bool good[N];

void dfs(int u, int p) 
{
	par[u] = p;
	tin[u] = ++timer;
	for (auto i : adj[u]) 
	{
		int v = i.fi, w = i.se;
		if (v == p) continue;
		h[v] = h[u] + w;
		dfs(v, u);
	}
	tout[u] = timer;
}

void dfs1(int u, int p) 
{
	if (u > n && k > h[u]) 
	{
		for (int i = 1; i * i <= (k-h[u]); i++) 
		{
			if ((k-h[u]) % i != 0) continue;
			if (mp[i] > 0 || mp[(k-h[u]) / i] > 0) 
			{
				good[u] = 1;
				break;
			}
		}
	}
	for (int i = 0; i <= n; i++) 
	{
		if (tin[u] <= tin[i] && tin[i] <= tout[u]) 
		{
			mp[h[i]-h[u]+s]++;
		}
	}
	for (auto i : adj[u]) 
	{
		int v = i.fi, w = i.se;
		if (v == p) continue;
		dfs1(v, u);
	}
	for (int i = 0; i <= n; i++) 
	{
		if (tin[u] <= tin[i] && tin[i] <= tout[u]) 
		{
			mp[h[i]-h[u]+s]--;
		}
	}
}

void solve()
{
	cin>>n>>m>>k>>s;
	++s;
	for (int i = 1; i <= n; i++) 
	{
		int p, l;
		cin>>p>>l;
		++l;
		// cout<<p<<" "<<i<<" "<<l<<endl;
		adj[p].pb({i, l});
	}
	for (int i = 1; i <= m; i++) 
	{
		int p, l;
		cin>>p>>l;
		++l;
		// cout<<p<<" "<<i+n<<" "<<l<<endl;
		adj[p].pb({i+n, l});
	}
	dfs(0, -1);
	dfs1(0, -1);
	mp.clear();
	for (int i = 0; i <= n; i++) mp[h[i]] = 1;
	for (int i = 1; i <= m; i++) 
	{
		// cout<<i+n<<" "<<h[i+n]<<endl;
		if (h[i+n] == k) cout<<"YES"<<endl;
		else if (h[i+n] > k) 
		{
			int u = i+n;
			bool check = 0;
			while (u != -1) 
			{
				// cout<<u<<" "<<k+h[u]-h[i+n]-s<<endl;
				if (mp[k+h[u]-h[i+n]-s]) 
				{
					check = 1;
					break;
				}
				u = par[u];
			}
			if (check) cout<<"YES";
			else cout<<"NO";
			cout<<endl;
		} else 
		{
			if (good[i+n]) 
			{
				cout<<"YES"<<endl;
				continue;
			}
			int u = i+n;
			bool check = 0;
			while (u != -1) 
			{
				u = par[u];
				if (u == -1) break;
				if (mp[k+h[u]-h[i+n]-s]) 
				{
					check = 1;
					break;
				}
			}
			if (check) 
			{
				cout<<"YES"<<endl;
				continue;
			}
			cout<<"NO"<<endl;
		}	
	}
}

/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/

signed main()
{
	bruh
	//freopen("input.inp","r",stdin);
	//freopen("output.inp","w",stdout);
	int t = 1;
	// cin>>t;
	while (t--)
	{
		solve();
		cout<<"\n";
	}
}

• Subtask 1: 33 / 33
• Subtask 2: 33 / 33
• Subtask 3: 34 / 34