백준 5014번 C++

#include <iostream>

#include <cstring>

#include <queue>

using namespace std;

int f, s, g, u, d;

int visited[1000001];

int bfs(int s) {

queue<int> q;

q.push(s);

visited[s] = 1;

while (!q.empty()) {

int x = q.front();

q.pop();

if (x == g)

return visited[x]-1;

int movestairs[2] = { x + u, x - d };

for (int k = 0; k < 2; k++) {

int ma = movestairs[k];

if (ma >= 1 && ma <= f){

if (visited[ma] ==0 ) {

q.push(ma);

visited[ma] = visited[x] + 1;

}

}

}

}

return -1;

}

int main(void) {

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

memset(visited, 0, sizeof(visited));

int ans = bfs(s);

if (ans == -1)

cout << "use the stairs";

else

cout << ans;

}