_1346.java

package com.fishercoder.solutions;

/**
 * 1346. Check If N and Its Double Exist
 *
 * Given an array arr of integers, check if there exists two integers N and M such that N is the double of M ( i.e. N = 2 * M).
 *
 * More formally check if there exists two indices i and j such that :
 *
 * i != j
 * 0 <= i, j < arr.length
 * arr[i] == 2 * arr[j]
 *
 * Example 1:
 * Input: arr = [10,2,5,3]
 * Output: true
 * Explanation: N = 10 is the double of M = 5,that is, 10 = 2 * 5.
 *
 * Example 2:
 * Input: arr = [7,1,14,11]
 * Output: true
 * Explanation: N = 14 is the double of M = 7,that is, 14 = 2 * 7.
 *
 * Example 3:
 * Input: arr = [3,1,7,11]
 * Output: false
 * Explanation: In this case does not exist N and M, such that N = 2 * M.
 *
 * Constraints:
 * 2 <= arr.length <= 500
 * -10^3 <= arr[i] <= 10^3
 * */
public class _1346 {
    public static class Solution1 {
        public boolean checkIfExist(int[] arr) {
            for (int i = 0; i < arr.length; i++) {
                for (int j = 0; j < arr.length; j++) {
                    if (i != j && (arr[i] * 2 == arr[j] || arr[i] == arr[j] * 2)) {
                        return true;
                    }
                }
            }
            return false;
        }
    }
}