ELEVTRBL

Problem Link

#include <iostream>

#include <vector>

#include <queue>

using namespace std;

const long N = 1000000;

long dist[N + 1];

void bfs(long s, long g, long u, long d, long f)

{

queue<long> q;

q.push(s);

while(!q.empty())

{

long currentFloor = q.front();

q.pop();

long floorDown = currentFloor - d;

long floorUp = currentFloor + u;

if(currentFloor == g)

{

break;

}

if(floorDown > 0 && floorDown <= f && dist[floorDown] == -1)

{

dist[floorDown] = dist[currentFloor] + 1;

q.push(floorDown);

}

if(floorUp <= f && dist[floorUp] == -1)

{

dist[floorUp] = dist[currentFloor] + 1;

q.push(floorUp);

}

}

}

int main()

{

long f,s, g, u, d;

cin >> f >> s >> g >> u >> d;

vector<long> graph[f + 1];

for(int i = 0; i < N + 1; i++)

{

dist[i] = -1;

}

dist[s] = 0;

bfs(s, g, u, d, f);

dist[g] != -1 ? cout << dist[g] : cout << "use the stairs";

}