## Finding duplicate integers in an array and display how many times they occurred

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in an integer array there is 1 to 100 number out of one is duplicate how to find

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I'm working on a code that prints out duplicated integers from an array with the number of their occurrence. I'm not allowed to use LINQ, just a simple code. I think I'm so close but confused about how to get a correct output:

class Program { static void Main(string[] args) { int[] array = { 10, 5, 10, 2, 2, 3, 4, 5, 5, 6, 7, 8, 9, 11, 12, 12 }; int count = 1; for (int i = 0; i < array.Length; i++) { for (int j = i; j < array.Length - 1 ; j++) { if(array[j] == array[j+1]) count = count + 1; } Console.WriteLine("\t\n " + array[i] + "occurse" + count); Console.ReadKey(); } } }

Since you can't use LINQ, you can do this with collections and loops instead:

static void Main(string[] args) { int[] array = { 10, 5, 10, 2, 2, 3, 4, 5, 5, 6, 7, 8, 9, 11, 12, 12 }; var dict = new Dictionary<int, int>(); foreach(var value in array) { if (dict.ContainsKey(value)) dict[value]++; else dict[value] = 1; } foreach(var pair in dict) Console.WriteLine("Value {0} occurred {1} times.", pair.Key, pair.Value); Console.ReadKey(); }

**Find the two repeating elements in a given array,** And all elements occur once except two numbers which occur twice. size n, when you see an element whose count is already set, print it as duplicate. if we xor all the elements in the array and all integers from 1 to n, then the result is X xor Y. Maximum subarray sum in array formed by repeating the given array k times. I'm working on a code that prints out duplicated integers from an array with the number of their occurrence. I'm not allowed to use LINQ, just a simple code. I think I'm so close but confused about

Use Group by:

int[] values = new []{1,2,3,4,5,4,4,3}; var groups = values.GroupBy(v => v); foreach(var group in groups) Console.WriteLine("Value {0} has {1} items", group.Key, group.Count());

**Find duplicates in O(n) time and O(1) extra space,** A simpler secondary DNS solution is just a few clicks away. Given an integer array such that every element occurs 3 times except one for the elimination of duplicate numbers in an array of values with C++ (and display unique numbers)?. Find duplicates in O(n) time and O(1) extra space | Set 1 Given an array of n elements which contains elements from 0 to n-1, with any of these numbers appearing any number of times. Find these repeating numbers in O(n) and using only constant memory space.

Let's take a look at a simpler example. Let's say we have the array `{0, 0, 0, 0}`

.

What will your code do?

It will first look to see how many items after the first item are equal to it. There are three items after the first that are equal to it.

Then it goes to the next item, and looks for all items after it that are equal to it. There are two. So far we're at 5, and we haven't even finished yet (we have one more to add), but there are only four items in the whole array.

Clearly we have an issue here. We need to ensure that when we've searched the array for duplicates of a given item that we don't search through it again for that same item. While there are ways of doing that, this fundamental approach is looking to be quite a lot of work.

Of course, there are different approaches entirely that we can take. Rather that going through each item and searching for others like it, we can loop through the array *once*, and add to a count of number of times we've found that character. The use of a `Dictionary`

makes this easy:

var dictionary = new Dictionary<int, int>(); foreach (int n in array) { if (!dictionary.ContainsKey(n)) dictionary[n] = 0; dictionary[n]++; }

Now we can just loop through the dictionary and see which values were found more than once:

foreach(var pair in dictionary) if(pair.Value > 1) Console.WriteLine(pair.Key);

This makes the code clear to read, obviously correct, and (as a bonus) quite a lot more efficient than your code, as you can avoid looping through the collection multiple times.

**How to find the duplicate elements in an array and count the ,** In this program, we need to print the duplicate elements present in the array. If a match is found which means the duplicate element is found then, display the Finding the indices of duplicate values in one array. % Assume they're integers Finding the indices of duplicate values in one array. I use the same solution

Here is an answer that avoids using Dictionaries. Since the OP said he is not familiar with them, this might give him a little insight into what Dictionaries do.

The downside to this answer is you have to enforce a limit on the max number in the array, and you can't have negative numbers. You'd never actually use this version in real code.

int[] array = { 10, 5, 10, 2, 2, 3, 4, 5, 5, 6, 7, 8, 9, 11, 12, 12 }; int[] count = new int[13]; foreach(int number in array) { // using the index of count same way you'd use a key in a dictionary count[number]++; } foreach(int c in count) { int numberCount = count[c]; if(numberCount > 0) { Console.WriteLine(c + " occurs " + numberCount + " times"); } }

**Program to print the duplicate elements of an array,** (1) Loop through the array (2) For each element, find array[absolute(array[i])] in function duplicates(arr) { // where we will store our duplicate values var dups Given an array A of length n, let h ← (new hash table) for 1 <= i <= n: if A[i] is present in h: return A[i] set h[A[i]] ← True return <no duplicates> Now, suppose that the array is of length n and only contains positive integers less than n. We can be sure (by the pigeonhole principle) that there is at least one duplicate. The bounds on

Ok I have modified your code. This should do the job:

class Program { static void Main(string[] args) { int[] array = { 10, 5, 10, 2, 2, 3, 4, 5, 5, 6, 7, 8, 9, 11, 12, 12 }; for (int i = 0; i < array.Length; i++) { int count = 0; for (int j = 0; j < array.Length; j++) { if (array[i] == array[j]) count = count + 1; } Console.WriteLine("\t\n " + array[i] + " occurs " + count + " times"); } Console.ReadKey(); } }

**Find all duplicates in an array in linear time (v1),** Jul 17, 2019 · For finding duplicate values in JavaScript array, you'll make use of Because we are only using one loop, our time complexity becomes O(n), Each test case contains an integer n which denotes number of elements of Array. We need to find the element that occurs more than once and whose index of the 2 Ways to find duplicate elements in an Array - Java Solution Hello guys, today, you will learn how to solve another popular coding problem. You have given an array of objects, which could be an array of integers and or array of Strings or any object which implements the Comparable interface.

**Find repeated number in array javascript,** I'm working on a code that prints out duplicated integers from an array with the number of their occurrence. I'm not allowed to use LINQ, just a simple code. C Program to Count Total Duplicate Elements in an Array Example. This program asks the user to enter Array Size and array elements. Next, it is going to count the total number of duplicate elements present in this array using For Loop.

**array_count_values - Manual,** array_count_values() returns an array using the values of array as keys and Throws E_WARNING for every element which is not string or integer. duplicate values from an array; array_values() - Return all the values of an I couldn't find a function for counting the values with case-insensitive Time:0.259949922562 Array is the collection of similar data type, In this program we find duplicate elements from an array, Suppose array have 3, 5, 6, 11, 5 and 7 elements, in this array 5 appear two times so this is our duplicate elements.

**C# Programming: From Problem Analysis to Program Design,** Write a program that reads data into an array of type int. Valid values Output a list of distinct entries and a count of how many times that entry occurred. Use the Logic to count duplicate elements in array. Step by step descriptive logic to count duplicate elements in array. Input size and elements in array from user. Store it in some variable say size and arr. Initialize another variable count with 0 to store duplicate count. To count total duplicate elements in given array we need two loops.

##### Comments

- "I'm not allowed to use LINQ" :P
- @sunflower I though you said u're not allowed to used linq?
- You grouping the same number and then get count of theme
- Thanks a lot ! I will read through using Dictionary since it looks like it's usefull ,and I don't have to wait to take it in class in next semester.
- It will report "10 occurs 2 times" twice though.
- That is right ,it sorts of working except for it prints out some values and their occurance more than one time.
- Yes, that's what happens in this example. To get rid of it, you either need to use another array variable or a Dictionary as shown in other examples. But I didn't use any other variable other than you already used in your example.
- I will go through it again ,but thank you for pushing it to this point :)
- Run your code against my sample input and see what you get.
- Thank you for helping :)
- While this code might be helpful, it would be
*more*helpful if you explained what the author was doing wrong and why your code fixes that problem.