Submission #416659

#	Time	Username	Problem	Language	Result	Execution time	Memory
416659		Dilshod_Imomov	Stations (IOI20_stations)	C++17	76 / 100	1103 ms	55540 KiB

stations

#include "stations.h"
#include <bits/stdc++.h>
using namespace std;
 
const int MAXN = 1e3 + 7;
 
void dfs( vector<vector<int>> adj, int v, int p, int h, vector<int> &lb, int &cnt ) {
	if ( h % 2 == 0 ) {
		lb[v] = cnt;
	}
	cnt++;
	for ( auto u: adj[v] ) {
		if ( u != p ) {
			dfs( adj, u, v, h + 1, lb, cnt );
		}
	}
	if ( h & 1 ) {
		lb[v] = cnt;
	}
	// cout << "-> " << v << " " << lb[v] << endl;
	cnt++;
}
 
 
vector<int> label(int n, int k, vector<int> U, vector<int> V) {
	vector < vector < int > > adj(n + 1);
	for ( int i = 0; i < n - 1; i++ ) {
		int u = U[i], v = V[i];
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	vector < int > lb(n);
	int cnt = 0;
	dfs( adj, 0, -1, 0, lb, cnt );
	return lb;
}
 
int find_next_station(int s, int t, vector<int> c) {
	int sz = c.size(), pr = -1;
	int tins = -1, touts = -1;
	vector < int > tin(sz), tout(sz);
	if ( c[0] > s ) { // s is in even layer, s in tin
		tins = s;
		if ( s == 0 ) {
			touts = c.back() + 1;
		}
		else {
			touts = c[sz - 2] + 1;
			pr = c.back();
			c.pop_back();
			sz--;
		}
		tin[0] = tins + 1;
		tout[0] = c[0];
		for ( int i = 1; i < sz; i++ ) {
			tin[i] = tout[i - 1] + 1;
			tout[i] = c[i];
		}
	}
	else { // s in odd layer
		touts = s;
		if ( sz == 1 ) {
			tins = s - 1;
			return c[0];
		}
		else {
			pr = c[0];
			c.erase(c.begin());
			sz--;
			tins = c[0] - 1;
		}
		tout[sz - 1] = s - 1;
		tin[sz - 1] = c[sz - 1];
		for ( int i = sz - 2; i >= 0; i-- ) {
			tout[i] = tin[i + 1] - 1;
			tin[i] = c[i];
		}
	}
	// cout << tins << ' ' << touts << ' ' << pr << endl;
	for ( int i = 0; i < sz; i++ ) {
		int u = c[i];
		// cout << tin[i] << " " << tout[i] << endl;
		if ( tin[i] <= t && tout[i] >= t ) {
			return u;
		}
	}
	assert( pr != -1 );
	return pr;
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:40:17: warning: variable 'touts' set but not used [-Wunused-but-set-variable]
   40 |  int tins = -1, touts = -1;
      |                 ^~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 50 / 61