NextGreaterElementI.java

/* (C) 2024 YourCompanyName */
package array;

/**
 * Created by gouthamvidyapradhan on 09/02/2018. You are given two arrays (without duplicates) nums1
 * and nums2 where nums1’s elements are subset of nums2. Find all the next greater numbers for
 * nums1's elements in the corresponding places of nums2.
 *
 * <p>The Next Greater Number of a number x in nums1 is the first greater number to its right in
 * nums2. If it does not exist, output -1 for this number.
 *
 * <p>Example 1: Input: nums1 = [4,1,2], nums2 = [1,3,4,2]. Output: [-1,3,-1] Explanation: For
 * number 4 in the first array, you cannot find the next greater number for it in the second array,
 * so output -1. For number 1 in the first array, the next greater number for it in the second array
 * is 3. For number 2 in the first array, there is no next greater number for it in the second
 * array, so output -1. Example 2: Input: nums1 = [2,4], nums2 = [1,2,3,4]. Output: [3,-1]
 * Explanation: For number 2 in the first array, the next greater number for it in the second array
 * is 3. For number 4 in the first array, there is no next greater number for it in the second
 * array, so output -1. Note: All elements in nums1 and nums2 are unique. The length of both nums1
 * and nums2 would not exceed 1000.
 */
public class NextGreaterElementI {

  /**
   * Main method
   *
   * @param args
   * @throws Exception
   */
  public static void main(String[] args) throws Exception {
    int[] A = {4, 1, 2};
    int[] B = {1, 3, 4, 2};
    int[] result = new NextGreaterElementI().nextGreaterElement(A, B);
    System.out.println(result);
  }

  public int[] nextGreaterElement(int[] nums1, int[] nums2) {
    int[] result = new int[nums1.length];
    for (int i = 0; i < nums1.length; i++) {
      int n = nums1[i];
      boolean found = false;
      int nF = 0;
      for (int j = 0; j < nums2.length; j++) {
        if (nums2[j] == n) {
          found = true;
        }
        if (found) {
          if (nums2[j] > n) {
            nF = nums2[j];
            break;
          }
        }
      }
      if (found) {
        result[i] = nF;
      } else {
        result[i] = -1;
      }
    }
    return result;
  }
}