Solve the Josephus problem. There are n people standing in a circle, numbered 1 to n. Starting from person 1, you count k people around the circle and eliminate the kth person. Counting then resumes from the next person, and the process repeats until only one person remains. Return the 1-based position of the survivor.
Examples:
Input: n = 7, k = 3
Output: 4
Explanation: Order of elimination is 3, 6, 2, 7, 5, 1, leaving 4
Input: n = 5, k = 2
Output: 3
Explanation: Order of elimination is 2, 4, 1, 5, leaving 3
Input: n = 1, k = 1
Output: 1
Explanation: With one person, that person survives
Input: n = 6, k = 2
Output: 5
Explanation: The survivor is at position 5
Input: n = 10, k = 2
Output: 5
Explanation: The survivor is at position 5
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