Counting repeated elements in an integer array

Question

I have an integer array crr array and I want to count elements  which occur repeatedly  First  I read the size of the array and initialize it with numbers read from the console  In the array new array  I store the elements that are repeated  The array times stores the number of consecutive occurrences of an element  Then  I try to search for the repeating sequences and print them in a specific format  However  it does not work      Get integer array size Scanner input   new Scanner System in   System out println  Enter array size      int size   input nextInt     int   crr array   new int size   int   new array  new int size   int   times   new int size       Read integers from the console System out println  Enter array elements      for  int i   0  i  lt  crr array length  i          crr array i    input nextInt        times i    1        Search for repeated elements for  int j   0  j  lt  crr array length  j          for  int i   j  i  lt  crr array length  i              if  crr array j     crr array i   amp  amp  j    i                new array i    crr array i               times i                            Printing output for  int i   0  i  lt   new array length  i          System out println   t    crr array i      t     new array i      t    times i         I want the output to look like this   There are  lt count of repeated element sequences gt  repeated numbers   lt repeated element gt    lt count gt  times       For example   There are 3 repeated numbers  22  2 times 4  3 times 1  2 times   How can I find the repeated elements and their counts  How can I print them as shown above

User · Answer

You have to use or read about associative arrays, or maps,..etc. Storing the the number of occurrences of the repeated elements in array, and holding another array for the repeated elements themselves, don't make much sense.

Your problem in your code is in the inner loop

 for (int j = i + 1; j < x.length; j++) {

        if (x[i] == x[j]) {
            y[i] = x[i];
            times[i]++;
        }

    }

User · Answer

with O n log n    int   arr1     your given array int   arr2   new int arr1 length   Arrays sort arr1    for  int i   0  i  lt  arr1 length  i          arr2 i         if  i 1  lt  arr1 length                 if  arr1 i     arr1 i   1                 arr2 i                 i                       for  int i   0  i  lt  arr1 length  i          if arr2 i  gt 0      System out println arr1 i          arr2 i

User · Answer

for  int i   0  i  lt  x length  i           for  int j   i   1  j  lt  x length  j               if  x i     x j                 y i    x i               times i

User · Answer

public class ArrayDuplicate   private static Scanner sc  static int totalCount   0       public static void main String   args            int n  num          sc   new Scanner System in           System out print  Enter the size of array              n  sc nextInt            int   a   new int n           for int i 0 i lt n i                 System out print  Enter the element at position   i                    num   sc nextInt                a enter image description here  1  i  num                    System out print  Elements in array are              for int i 0 i lt a length i                System out print a i                System out println            duplicate a           System out println  There are   totalCount   repeated numbers                public static void duplicate int   a           int j   0 count  recount  temp          for int i 0  i lt a length i                 count   0              recount   0              j i 1              while j lt a length                   if a i   a j                       count                    j                              if count gt 0                   temp   a i                   for int x 0 x lt i x                         if a x   temp                          recount                                      if recount  0                                        totalCount                        System out println  a i        count   times

User · Answer

If you have values in a short set of possible values then you can use something like Counting Sort   If not you have to use another data structure like a Dictionary  in java a Map  int   array Map lt Integer  Integer gt     where Key   array value for example array i  and value   a counter  Example   int   array   new int  50   Map lt Integer Integer gt  counterMap   new HashMap lt  gt        fill the array      for int i 0 i lt array length i              if counterMap containsKey array i               counterMap put array i   counterMap get array i   1              else            counterMap put array i   1

User · Answer

This kind of problems can be easy solved by dictionaries  HashMap in Java          The solution itself    HashMap lt Integer  Integer gt  repetitions   new HashMap lt Integer  Integer gt        for  int i   0  i  lt  crr array length    i          int item   crr array i          if  repetitions containsKey item             repetitions put item  repetitions get item    1         else           repetitions put item  1             Now let s print the repetitions out   StringBuilder sb   new StringBuilder       int overAllCount   0     for  Map Entry lt Integer  Integer gt  e   repetitions entrySet            if  e getValue    gt  1              overAllCount    1             sb append   n              sb append e getKey               sb append                  sb append e getValue               sb append   times                   if  overAllCount  gt  0          sb insert 0    repeated numbers           sb insert 0  overAllCount         sb insert 0   There are            System out print sb toString

User · Answer

package com core java   import java util Arrays  import java util Scanner   public class Sim       public static void main String   args             Scanner input   new Scanner System in           System out println  Enter array size              int size   input nextInt             int   array   new int size               Read integers from the console         System out println  Enter array elements              for  int i   0  i  lt  array length  i                  array i    input nextInt                      Sim s   new Sim            s find array              public void find int   arr            int count   1          Arrays sort arr            for  int i   0  i  lt  arr length  i                   for  int j   i   1  j  lt  arr length  j                      if  arr i     arr j                         count                                                if  count  gt  1                    System out println                    System out println  repeated element in array     arr i           count     time s                     i   i   count - 1                            count   1

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public static void duplicatesInteger int arr         Arrays sort arr              int count 0      Set s new HashSet        for int i 0 i lt  arr length-1 i             for int j i 1 j lt  arr length-1 j                 if arr i   arr j   amp  amp  s add arr i                     count count 1                                                                    System out println count

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public class DuplicationNoInArray                    param args                   the command line arguments             public static void main String   args  throws Exception           int   arr     1  2  3  4  5  1  2  8            int   result   new int 10           int counter   0  count   0          for  int i   0  i  lt  arr length  i                  boolean isDistinct   false              for  int j   0  j  lt  i  j                      if  arr i     arr j                         isDistinct   true                      break                                              if   isDistinct                    result counter      arr i                                   for  int i   0  i  lt  counter  i                  count   0              for  int j   0  j  lt  arr length  j                      if  result i     arr j                         count                                                 System out println result i            count

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public static void main String   args        Scanner input new Scanner System in       int   numbers new int 5       String x null      System out print  enter the number 10     n        for int i 0 i lt 5 i             numbers i    input nextInt              System out print  Numbers     count    n        int count 1      Arrays sort numbers       for int z 0 z lt 5 z             for int j 0 j lt z j                 if numbers z   numbers j   amp  j  z                   count count 1                                  System out print numbers z    -   count   n            count 1

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package jaa stu com wordgame          Created by AnandG on 3 14 2016      public final class NumberMath       public static boolean isContainDistinct int   arr             boolean isDistinct   true          for  int i   0  i  lt  arr length  i                            for  int j   0  j  lt  arr length  j                      if  arr i     arr j   amp  amp  i  j                        isDistinct   false                      break                                                     return isDistinct            public static boolean isContainDistinct float   arr             boolean isDistinct   true          for  int i   0  i  lt  arr length  i                            for  int j   0  j  lt  arr length  j                      if  arr i     arr j   amp  amp  i  j                        isDistinct   false                      break                                                     return isDistinct            public static boolean isContainDistinct char   arr             boolean isDistinct   true          for  int i   0  i  lt  arr length  i                            for  int j   0  j  lt  arr length  j                      if  arr i     arr j   amp  amp  i  j                        isDistinct   false                      break                                                     return isDistinct            public static boolean isContainDistinct String   arr             boolean isDistinct   true          for  int i   0  i  lt  arr length  i                            for  int j   0  j  lt  arr length  j                      if  arr i     arr j   amp  amp  i  j                        isDistinct   false                      break                                                     return isDistinct            public static int   NumberofRepeat int   arr             int   repCount  new int arr length           for  int i   0  i  lt  arr length  i                            for  int j   0  j  lt  arr length  j                      if  arr i     arr j                          repCount i   1                                                     return repCount            call  by NumberMath isContainDistinct array  for find is it contains repeat or not   call  by int   repeat NumberMath NumberofRepeat array  for find repeat count  Each location contains how many repeat corresponding value of array

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public class FindRepeatedNumbers     public static void main String   args              int num    1 3 2 4 1 2 4 6 7 5              Arrays sort num      for int j 1 j lt num length j                   if num j   num j-1                     System out println num j

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private  static void getRepeatedNumbers         int    numArray    2 5 3 8 1 2 8 3 3 1 5 7 8 12 134       Set lt Integer gt  nums   new HashSet lt Integer gt              for  int i  0  i lt numArray length  i              if nums contains numArray i                continue              int count  1              for  int j   i 1  j  lt  numArray length  j                      if numArray i     numArray j                         count                                                                     System out println  quot The  quot  numArray i    quot  is repeated  quot  count  quot  times  quot                nums add numArray i

[java] Counting repeated elements in an integer array

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