Submission #375354

#	Time	Username	Problem	Language	Result	Execution time	Memory
375354		wind_reaper	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	0 / 100	1 ms	384 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

const int INF = 1e9;

int32_t main(){
	ios_base::sync_with_stdio(false); 
	cin.tie(NULL); 
	
	int n, m;
	cin >> n >> m;

/*	vector<vector<array<int, 2>>> adj(n);
	int src, dest;
	for(int i = 0; i < m; i++){
		int b, p;
		cin >> b >> p;
		if(i == 0) src = b;
		if(i == 1) dest = b;
		for(int j = b+p; j < n; j += p)
			adj[j-p].push_back({j, 1});
		for(int j = b-p; j >= 0; j -= p)
			adj[j+p].push_back({j, 1});
	}

	vector<int> dist(n, INF);
	dist[src] = 0;
	priority_queue<array<int, 2>, vector<array<int, 2>>, greater<array<int, 2>>> pq;
	pq.push({0, src});

	while(!pq.empty()){
		auto [d, node] = pq.top();
		pq.pop();
		for(auto& [v, nd] : adj[node]){
			if(dist[v] <= dist[node] + nd)
				continue;
			dist[v] = dist[node] + nd;
			pq.push({dist[v], v});
		}
	}
	
	cout << (dist[dest] == INF ? -1 : dist[dest]) << '\n';*/

	vector<vector<array<int, 3>>> adj(n);
	vector<array<int, 2>> d(n);
	int src, dest;
	for(int i = 0; i < m; i++){
		int b, p;
		cin >> b >> p;
		d[i] = {b, p};
		if(i == 0) src = b;
		if(i == 1) dest = b;
		for(int j = b+p; j < n; j+=p)
			adj[j-p].push_back({j, 1, i});
		for(int j = b-p; j >= 0; j-=p)
			adj[j+p].push_back({j, 1, i});
	}

	vector<int> dist(n, INF);
	dist[src] = 0;
	priority_queue<array<int, 3>, vector<array<int, 3>>, greater<array<int, 3>>> pq;
	pq.push({0, src});

	while(!pq.empty()){
		auto [t, node, edge_source] = pq.top();
		pq.pop();
		for(auto& [v, nd, ne_s] : adj[node]){
			//to access this particular edge, edge_source -> ne_s -> node
			//abs(d[ne_s][0] - d[edge_source][0]) / d[edge_source][1] + abs(d[v][0] - d[ne_s][0]) / d[ne_s][1]
			int inc = (abs(d[ne_s][0] - d[edge_source][0]))/d[edge_source][1] + abs(d[v][0] - d[ne_s][0])/d[ne_s][1];
			if(dist[v] <= inc)
				continue;
			dist[v] = inc;
			pq.push({inc, v, ne_s}); 
		}
	}

	cout << (dist[dest] == INF ? -1 : dist[dest]) << '\n'; 
	return 0; 
}

Compilation message (stderr)

skyscraper.cpp: In function 'int32_t main()':
skyscraper.cpp:79:20: warning: 'dest' may be used uninitialized in this function [-Wmaybe-uninitialized]
   79 |  cout << (dist[dest] == INF ? -1 : dist[dest]) << '\n';
      |                    ^
skyscraper.cpp:61:10: warning: 'src' may be used uninitialized in this function [-Wmaybe-uninitialized]
   61 |  dist[src] = 0;
      |          ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43