MaximumFrequencyNumber.java

// Maximum Frequency Number
// Send Feedback
// You are given an array of integers that contain numbers in random order.
// Write a program to find and return the number which occurs the maximum times
// in the given input.
// If two or more elements are having the maximum frequency, return the element
// which occurs in the array first.
// Input Format:
// The first line of input contains an integer, that denotes the value of the
// size of the array. Let us denote it with the symbol N.
// The following line contains N space separated integers, that denote the value
// of the elements of the array.
// Output Format :
// The first and only line of output contains most frequent element in the given
// array.
// Constraints:
// 0 <= N <= 10^8
// Time Limit: 1 sec
// Sample Input 1 :
// 13
// 2 12 2 11 12 2 1 2 2 11 12 2 6
// Sample Output 1 :
// 2
// Sample Input 2 :
// 6
// 7 2 2 4 8 4
// Sample Output 2 :
// 2
// Explanation:
// Here, both element '2' and element '4' have same frequency but '2' ocurr
// first in orignal array that's why we are returning '2' as output.

import java.util.HashMap;

public class Solution {

    public static int maxFrequencyNumber(int[] arr) {
        /*
         * Your class should be named Solution
         * Don't write main().
         * Don't read input, it is passed as function argument.
         * Return output and don't print it.
         * Taking input and printing output is handled automatically.
         */
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < arr.length; i++) {
            if (map.containsKey(arr[i])) {
                map.put(arr[i], map.get(arr[i]) + 1);
            } else {
                map.put(arr[i], 1);
            }
        }

        int maxOccuringNumber = 0;
        int occurenceTimes = Integer.MIN_VALUE;
        for (int i : arr) {
            if (map.containsKey(i)) {
                if (map.get(i) > occurenceTimes) {
                    maxOccuringNumber = i;
                    occurenceTimes = map.get(i);
                }
            }
        }

        return maxOccuringNumber;
    }
}