数组中的其值等于频率的最大元素
原文：https://www.geeksforgeeks.org/maximum-element-in-an-array-which-is-equal-to-its-frequency/
给定一个大小为N的整数arr[]数组，任务是在数组中查找其频率等于其值的最大元素。
示例：
输入：
arr[] = {3, 2, 2, 3, 4, 3}输出：3
元素 2 的频率为 2
元素 3 的频率为 3
元素 4 的频率为 1
2 和 3 是与其值具有相同频率的元素，最大为 3。
输入：
arr[] = {1, 2, 3, 4, 5, 6}输出：1
方法：使用映射存储数组的每个元素的频率，最后找出那些频率等于其值的元素的最大值。
下面是上述方法的实现：
CPP
// C++ program to find the maximum element
// whose frequency equals to it's value
#include <bits/stdc++.h>
using namespace std;
// Function to find the maximum element
// whose frequency equals to it's value
int find_maxm(int arr[], int n)
{
// Hash map for counting frquency
map<int, int> mpp;
for (int i = 0; i < n; i++) {
// Counting freq of each element
mpp[arr[i]] += 1;
}
int ans = 0;
for (auto x : mpp)
{
int value = x.first;
int freq = x.second;
// Check if value equls to frequency
// and it is the maximum element or not
if (value == freq) {
ans = max(ans, value);
}
}
return ans;
}
// Driver code
int main()
{
int arr[] = { 3, 2, 2, 3, 4, 3 };
// Size of array
int n = sizeof(arr) / sizeof(arr[0]);
// Function call
cout << find_maxm(arr, n);
return 0;
}
Java
// Java program to find the maximum element
// whose frequency equals to it's value
import java.util.*;
class GFG{
// Function to find the maximum element
// whose frequency equals to it's value
static int find_maxm(int arr[], int n)
{
// Hash map for counting frquency
HashMap<Integer,Integer> mp = new HashMap<Integer,Integer>();
for (int i = 0; i < n; i++) {
// Counting freq of each element
if(mp.containsKey(arr[i])){
mp.put(arr[i], mp.get(arr[i])+1);
}else{
mp.put(arr[i], 1);
}
}
int ans = 0;
for (Map.Entry<Integer,Integer> x : mp.entrySet())
{
int value = x.getKey();
int freq = x.getValue();
// Check if value equls to frequency
// and it is the maximum element or not
if (value == freq) {
ans = Math.max(ans, value);
}
}
return ans;
}
// Driver code
public static void main(String[] args)
{
int arr[] = { 3, 2, 2, 3, 4, 3 };
// Size of array
int n = arr.length;
// Function call
System.out.print(find_maxm(arr, n));
}
}
// This code is contributed by 29AjayKumar
Python3
# Python3 program to find the maximum element
# whose frequency equals to it's value
# Function to find the maximum element
# whose frequency equals to it's value
def find_maxm(arr, n) :
# Hash map for counting frquency
mpp = {}
for i in range(0,n):
# Counting freq of each element
if(arr[i] in mpp):
mpp.update( {arr[i] : mpp[arr[i]] + 1} )
else:
mpp[arr[i]] = 1
ans = 0
for value,freq in mpp.items():
# Check if value equls to frequency
# and it is the maximum element or not
if (value == freq):
ans = max(ans, value)
return ans
# Driver code
arr = [ 3, 2, 2, 3, 4, 3 ]
# Size of array
n = len(arr)
# Function call
print(find_maxm(arr, n))
# This code is contributed by Sanjit_Prasad
C
// C# program to find the maximum element
// whose frequency equals to it's value
using System;
using System.Collections.Generic;
class GFG{
// Function to find the maximum element
// whose frequency equals to it's value
static int find_maxm(int []arr, int n)
{
// Hash map for counting frquency
Dictionary<int,int> mp = new Dictionary<int,int>();
for (int i = 0; i < n; i++) {
// Counting freq of each element
if(mp.ContainsKey(arr[i])){
mp[arr[i]] = mp[arr[i]]+1;
}else{
mp.Add(arr[i], 1);
}
}
int ans = 0;
foreach (KeyValuePair<int,int> x in mp)
{
int value = x.Key;
int freq = x.Value;
// Check if value equls to frequency
// and it is the maximum element or not
if (value == freq) {
ans = Math.Max(ans, value);
}
}
return ans;
}
// Driver code
public static void Main(String[] args)
{
int []arr = { 3, 2, 2, 3, 4, 3 };
// Size of array
int n = arr.Length;
// Function call
Console.Write(find_maxm(arr, n));
}
}
// This code is contributed by Rajput-Ji
输出：
3
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