题目

• 原题连接：287. 寻找重复数

1- 思路

• 快慢指针

2- 实现

⭐287. 寻找重复数——题解思路

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

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


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

3- ACM 实现

public class duplicateNum {
    public static int findDuplicate(int[] nums){
        // 快慢指针
        int slow = nums[0];
        int fast = nums[0];

        // 出发
        do{
            slow = nums[slow];
            fast = nums[nums[fast]];

        }while(slow!=fast);

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

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] nums = new int[n];
        for(int i = 0 ; i < n;i++){
            nums[i] = sc.nextInt();
        }
        System.out.println("结果是"+findDuplicate(nums));
    }
}