BFS | 3278 | Catch That Cow

#include <cstdio>
#include <iostream>
#include <cstring>
#include <queue>
using namespace std;

const int M = 200005;

struct Node {
int a;
int step;
Node(int _a, int _step) : a(_a), step(_step) {}
};

int n, k;
queue<struct Node> que;
bool visited[M];

int getPlace(int i, int x)
{
if(i == 1)
return x - 1;
if(i == 2)
return x + 1;
if(i == 3)
return x << 1;
}

bool check(int x)
{
if(x >= 0 && x <= 200000)
return true;
return false;
}

int bfs()
{
while(!que.empty())
que.pop();
memset(visited, false, sizeof(visited));

que.push(Node(n, 1));
visited
= true;
while (!que.empty()) {
struct Node tmp = que.front();
que.pop();
for (int i = 1; i <= 3; i++) {
int x = getPlace(i, tmp.a);
if (check(x) && !visited[x]) {
if (x == k)
return tmp.step;
else {
que.push(Node(x, tmp.step + 1));
visited[x] = true;
}
}
}
}
}

int main()
{
while (scanf("%d%d", &n, &k) != EOF) {
if (n >= k)  printf("%d\n", n - k);
else           printf("%d\n", bfs());
}
}