Recursive-Joseph ring

2020-04-10 11:40:30

Problem Description:

The n numbers 0,1,, n-1 are arranged in a circle, starting with the number 0, and deleting the mth number from this circle each time. Find the last number left in this circle.

For example, the 5 digits 0, 1, 2, 3, and 4 form a circle, and the third digit is deleted every time from the digit 0, then the first 4 digits deleted are 2, 0, 4, 1, and so on. The remaining number is 3.

Example 1:

Input: n = 5, m = 3 
Output: 3

Example 2:

Input: n = 10, m = 17 
Output: 2

limit:

• 1 <= n <= 10^5
• 1 <= m <= 10^6

Problem solving:

Use recursive solution to solve in O (n) time complexity.

Time complexity: O (n)

    public int lastRemaining(int n, int m) {
        if (n == 1) return 0;
        return (lastRemaining(n - 1, m) + m) % n;
    }