UVa 694

From Algorithmist

Contents 1 694 - The Collatz Sequence 2 Summary 3 Explanation 4 Optimizations 5 Gotchas 6 Input 7 Output 8 See Also

[edit] 694 - The Collatz Sequence

• http://icpcres.ecs.baylor.edu/onlinejudge/index.php?option=com_onlinejudge&page=show_problem&problem=635

[edit] Summary

The Collatz Sequence, also known as the 3n+1 sequence or hailstone numbers, is a sequence of numbers that will eventually enter a 4, 2, 1 loop. This problem requires you to count how many steps it takes before reaching 1, or a specified limit.

[edit] Explanation

A "follow the instructions" problem. See also UVa 100

[edit] Optimizations

[edit] Gotchas

[edit] Input

3 100
34 100
75 250
27 2147483647
101 304
101 303
-1 -1

[edit] Output

Case 1: A = 3, limit = 100, number of terms = 8
Case 2: A = 34, limit = 100, number of terms = 14
Case 3: A = 75, limit = 250, number of terms = 3
Case 4: A = 27, limit = 2147483647, number of terms = 112
Case 5: A = 101, limit = 304, number of terms = 26
Case 6: A = 101, limit = 303, number of terms = 1

[edit] See Also

• UVa 100
• UVa 371