dominant number with map

Dominant Number.cpp

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+//  Dominant Number
+// Moderate
+// 0/80
+// Average time to solve is 15m
+// Asked in company
+// Problem statement
+// You are given an array of integers 'ARR' of size N. Your task is to find the dominant number in the array.
+
+// A dominant number in an array is an integer that occurs more than N/3 times in the array, where N is the array’s length.
+
+// Note:
+
+// 1. There will be only one such element (if it exists).
+// 2. If there is no such element in the array, return -1.
+// For Example:
+// If the given array ARR = {3,3,3,1,5,6,3} we can see that here 3 occurs 4 times in the array, which is greater than 7/3(N/3), so the dominant number here is 3.
+// Note:
+
+// Try to solve the problem in linear time complexity
+// Detailed explanation ( Input/output format, Notes, Images )
+// Constraints:
+// 1 <= T <= 100
+// 1 <= N<= 10^4
+// 0 ≤ ARR[I] ≤ 10^5
+
+// Time Limit: 1 sec
+// Sample Input 1 :
+// 3
+// 6
+// 3 1 1 8 1 2
+// 3
+// 1 2 4
+// 4
+// 3 2 1 3
+// Sample Output 1 :
+// 1
+// -1
+// 3
+// Explanation of The Sample Input 1:
+// For the first test case:
+// The given array is {3,1,1,8,1,2} we can see that 3 occurred three times in the array, which is greater than 6/3, so the dominant number will be 3. 
+
+// For the second test case:
+// The given array is {1,2,4} we can see that no number here is repeated more than once, so the answer here will be -1.
+
+// For the third test case
+// The given array is {3,2,1,3} we can see that  3 occurred two times in the array, which is greater than 4/3, so the dominant number will be 3. 
+// Sample Input 2 :
+// 3
+// 4
+// 4 4 4 1
+// 7
+// 5 6 6 4 3 2 6
+// 8
+// 1 9 8 4 5 5 5 5
+// Sample Output 2 :
+// 4
+// 6
+// 5
+
+
+#include <bits/stdc++.h> 
+int dominantNumber(int* arr, int n) 
+{
+	// Write your code here.
+	int d=n/3;
+	unordered_map<int,int>mp;
+	for(int i=0;i<n;i++){
+		mp[arr[i]]++;
+	}
+	for(auto i:mp){
+		if(i.second>d){
+			return i.first;
+		}
+	}
+	return -1;
+
+}