Happy Numbers,Trapping of Rainwater

package Interview_practice; import java.util.HashSet; import java.util.Scanner; public class HappyNumber { public static void main(String[] args) { System.out.println("Enter Number To find happynumber :"); Scanner sc = new Scanner(System.in); int num = sc.nextInt(); if (happynum(num) == true) { System.out.println("Happy number"); } else { System.out.println("Not Happy number"); } sc.close(); } public static boolean happynum(int num) { HashSet<Integer> seen = new HashSet<Integer>();// store and find repeated num while (num != 1 && !seen.contains(num)) { seen.add(num); num = findhappy(num); } if (num == 1) { return true; } else { return false; } } public static int findhappy(int num) { int total = 0; while (num > 0) { int n = num % 10; total += n * n; num = num / 10; } return total; } } 

package Afternoon; public class Trapping_of_Rainwater { public static void main(String[] args) { int[] heigth = { 0, 4, 5, 1}; int[] left = new int[heigth.length]; int[] rigth = new int[heigth.length]; int n = findtrapWater(heigth, left, rigth); System.out.println("Trapping_of_Rainwater :" + n + " units."); } private static int findtrapWater(int[] heigth, int[] left, int[] rigth) { int max = 0; for (int i = 0; i < heigth.length; i++) { if (heigth[i] >= max) { max = heigth[i]; } left[i] = max;//0 4 5 5 } max = 0; for (int i = heigth.length - 1; i >= 0; i--) { if (heigth[i] >= max) { max = heigth[i]; } rigth[i] = max;//5 5 5 1 } int total = 0; for (int i = 0; i < heigth.length; i++) { int minHeigth = 0; if (left[i] < rigth[i]) { minHeigth = left[i]; } else { minHeigth = rigth[i]; } //heigth[i] 0 4 5 1 total += minHeigth - heigth[i];//0-0+4-4+5-5+1-1 } return total; } }