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  1. #include<iostream>
  2. #include<cstring>
  3. #include<queue>
  4. using namespace std;
  5. int d[100000];
  6. const int MAX = 100000;
  7. int n, m;
  8. int main() {
  9. 	cin >> n >> m;
  10. 	queue<int>q;
  11. 	queue<int>next_q;
  12. 	memset(d, -1, sizeof(d));
  13. 	d[n] = 0;
  14. 	q.push(n);
  15.  
  16. 	while (!q.empty()) {
  17. 		int x = q.front();
  18. 		q.pop();
  19. 		if (2 * x < MAX && d[2 * x] == -1) {
  20. 			q.push(2 * x);
  21. 			d[2 * x] = d[x];
  22. 		}
  23.  
  24. 		if (x - 1 >= 0 && d[x - 1] == -1) {
  25. 			d[x - 1] = d[x] + 1;
  26. 			next_q.push(x - 1);
  27. 		}
  28. 		if (x + 1 < MAX && d[x + 1] == -1) {
  29. 			d[x + 1] = d[x] + 1;
  30. 			next_q.push(x + 1);
  31. 		}
  32. 		if (q.empty()) {
  33. 			q = next_q;
  34. 			next_q = queue<int>();
  35. 		}
  36. 	}
  37. 	if (d[m] != -1) {
  38. 		cout << d[m];
  39. 	}
  40. 	return 0;
  41. }
Success #stdin #stdout 0.01s 15632KB
comments (?)
stdin
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50000 100000
stdout
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Standard output is empty
https://ideone.com/xq0nwJ
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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