Submission #1080123

#	Time	Username	Problem	Language	Result	Execution time	Memory
1080123		Jawad_Akbar_JJ	Stations (IOI20_stations)	C++17	0 / 100	549 ms	940 KiB

stations

#include <iostream>
#include <vector>

using namespace std;
const int N1 = 1005;
vector<int> nei[N1];
int d[N1];
bool seen[N1];

vector<int> label(int n, int k, vector<int> u, vector<int> v){
	bool t = 1;
	for (int i=0;i<n-1;i++){
		nei[u[i]].push_back(v[i]);
		nei[v[i]].push_back(u[i]);
		d[u[i]]++;
		d[v[i]]++;
		t &= min(u[i], v[i]) == i / 2;
		t &= max(u[i], v[i]) == i+1;
	}
	vector<int> lab(n, 0);
	
	if (t){
		for (int i=0;i<n;i++)
			lab[i] = i+1;
		return lab;
	}
	if (k == 1e9){
		for (int i=0;i<n-1;i++){
			lab[u[i]] += (1<<v[i]);
			lab[v[i]] += (1<<u[i]);
		}
		lab[0] += 1e8;
		return lab;
	}

	int mx = 0, mn = 0;
	for (int i=0;i<n;i++){
		if (d[i] > d[mx])
			mx = i;
		if (d[i] < d[mn])
			mn = i;
	}

	if (d[mx] <= 2){
		int cur, lb = 0;
		for (int i=0;i<n;i++)
			if (d[i] == 1)
				cur = i;
			
		while (cur != -1){
			int ncur = -1;
			lab[cur] = lb++;
			seen[cur] = 1;
			for (int i : nei[cur])
				if (!seen[i])
					ncur = i;
			cur = ncur;
		}
		return lab;
	}

	return lab;

}

int ver;
bool dfs(int u, int s, int t, int p = -1){
	if (u == t)
		return 1;
	seen[u] = 1;
	for (int i : nei[u]){
		if (seen[i])
			continue;
		bool b = dfs(i, s, t, u);
		if (b and u == s)
			ver = i;
		if (b)
			return 1;
	}
	return 0;
}

int find_next_station(int s, int t, vector<int> lab){
	int n = lab.size();

	for (int i=0;i<n;i++)
		nei[i].clear(), seen[i] = 0;

	// if (lab[0] > 1e8){
	// 	for (int i=0;i<n;i++)
	// 		if (lab[i] == s){
	// 			s = i;
	// 			break;
	// 		}
	// 	for (int i=0;i<n;i++)
	// 		if (lab[i] == t){
	// 			t = i;
	// 			break;
	// 		}

	// 	lab[0] -= 1e8;
	// 	for (int i=0;i<n;i++){
	// 		for (int j=0;j<n;j++)
	// 			if ((1<<j) & lab[i])
	// 				nei[i].push_back(j);
	// 	}
	// 	lab[0] += 1e8;
	// 	ver = -1;
	// 	bool b = dfs(s, s, t);
	// 	if (ver == -1)
	// 		return lab[0];
	// 	return lab[ver];
	// }

	bool tt = true, t2 = true;
	for (int i=0;i<n;i++){
		tt &= lab[i] == i+1;
		if (lab[i] > n)
			t2 = false;
	}
 
	if (tt and lab[0] == 1){
		if (s < t){
			for (int i=1;i<=30;i++)
				if ((t>>i) == s)
					return (t >> (i-1));
			return s / 2;
		}
		else{
			return s / 2;
		}
	}

	if (t2){
		if (s > t)
			return s - 1;
		return s + 1;
	}
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:139:1: warning: control reaches end of non-void function [-Wreturn-type]
  139 | }
      | ^
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:52:11: warning: 'cur' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |    lab[cur] = lb++;
      |           ^

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