leetcode 力扣 287 寻找重复数

假期开组会，没时间看二分法了，只能用双指针模拟链表

寻找链表的入口

class Solution {
    public int findDuplicate(int[] nums) {
        int slow = 0;
        int fast = 0;

        do {
            slow = nums[slow];
            fast = nums[nums[fast]];
        } while (slow != fast);

        slow = 0;
        while (slow != fast) {
            slow = nums[slow];
            fast = nums[fast];
        }

        return slow;
    }
}