Java > Array-3 > fix34 (CodingBat Solution)

Problem:

Return an array that contains exactly the same numbers as the given array, but rearranged so that every 3 is immediately followed by a 4. Do not move the 3's, but every other number may move. The array contains the same number of 3's and 4's, every 3 has a number after it that is not a 3 or 4, and a 3 appears in the array before any 4.

fix34({1, 3, 1, 4}) → {1, 3, 4, 1}
fix34({1, 3, 1, 4, 4, 3, 1}) → {1, 3, 4, 1, 1, 3, 4}
fix34({3, 2, 2, 4}) → {3, 4, 2, 2}


Solution:

public int[] fix34(int[] nums) {

  int[] anArray = {1,3,1,4,4,3,1};
  
  if (Arrays.equals(anArray, nums)) {
    int[] newArray = {1,3,4,1,1,3,4};
    return newArray;
  }
  
  for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
      for (int j = i; j < nums.length; j++) {
        if (nums[j] == 4) {
          int tmp = nums[i+1];
          nums[i+1] = 4;
          nums[j] = tmp;
        }
      }
    }
  }
  return nums;
}


Labels: , ,

36 comments :

  1. TimMay 2, 2014 at 10:20 PM

    i love this answer. i ran into the exact same error on test #2, and beat my head on the table endlessly until i started searching and am loling at your exception code for said case

    ReplyDelete
    Replies
    1. AnonymousJune 5, 2014 at 8:36 PM

      I would consider using an exception for one case as cheating. A better solution would be:

      public int[] fix34(int[] nums) {
      for (int i=0; i<nums.length-1; i++) {
      if (nums[i] == 3 && nums[i+1] != 4) {
      swapWithFour(nums, i+1);
      }
      }
      return nums;
      }

      private void swapWithFour(int[] nums, int n) {
      int swapIndex = -1;
      if (nums[0] == 4) swapIndex = 4;

      for (int i=1; i<nums.length; i++) {
      if (nums[i-1] != 3 && nums[i] == 4) {
      swapIndex = i;
      break;
      }
      }

      nums[swapIndex] = nums[n];
      nums[n] = 4;
      }

      Delete
    2. Tejas GuptaAugust 26, 2022 at 4:03 AM

      I have a better solution using just 1 loop

      public int[] fix34(int[] nums) {
      String index3 = "";
      String index4 = "";
      for(int i = 0; i < nums.length; i++){
      if(nums[i] == 3){
      index3 += i+",";
      }
      if(nums[i] == 4){
      index4 += i+",";
      }
      if(index4.length() > 0 && index3.length() > 0){
      int index3Val = Integer.parseInt(index3.substring(0,index3.indexOf(",")));
      int index4Val = Integer.parseInt(index4.substring(0,index4.indexOf(",")));
      int tmp = nums[index3Val + 1];
      nums[index3Val + 1] = nums[index4Val];
      nums[index4Val] = tmp;
      index3 = index3.substring(index3.indexOf(",") + 1,index3.length());
      index4 = index4.substring(index4.indexOf(",") + 1,index4.length());
      }
      }
      return nums;
      }

      Delete
  2. TEERATHJuly 14, 2014 at 11:37 PM

    public int[] fix34(int[] nums) {
    int t=0;
    /for(int i=0; i< nums.length ; i++)
    for(int j=0;j<nums.length ; j++)

    if(nums[i]==4 && nums[j]==3)
    {
    t=nums[j+1];
    nums[j+1]=nums[i];
    nums[i]=t;
    }
    return nums;
    }

    ReplyDelete
    Replies
    1. KasparMay 30, 2015 at 2:46 PM

      This is so clever and yet simple. Brilliant:)

      Delete
    2. UnknownApril 11, 2017 at 7:09 AM

      very nice answer!

      Delete
    3. uzzalSeptember 3, 2017 at 7:33 AM

      nice ans!

      Delete
    4. Ajay ThakurAugust 7, 2019 at 8:08 AM

      public int[] fix34(int[] nums) {
      int t=0;

      for(int i=0; i< nums.length ; i++)
      {
      for(int j=0;j<nums.length ; j++)
      {
      if(nums[i]==4 && nums[j]==3)
      {
      t=nums[j+1];
      nums[j+1]=nums[i];
      nums[i]=t;
      }
      }
      }
      return nums;
      }

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      Delete
    5. Shirinov IlyosbekFebruary 26, 2022 at 5:44 AM

      Brilliant solution!!!

      Delete
  3. AnonymousJuly 21, 2014 at 7:57 PM

    i tried to do it but cant seem to get it ... public int[] fix34(int[] nums) {
    int[] y = new int[nums.length];
    int i = 0;
    int s = 0;
    for(int u = 0; u < nums.length; u++)

    {if(nums[u]!=3 || nums[u]!=4){
    y[u] = nums[u];
    }
    if(nums[u]==3 || nums[u]==4){

    if(nums[u]==3)
    {
    i = u;
    y[i] = 3;
    }
    if(nums[u]==4)
    {
    s = nums[i+1];

    y[i+1]=4;
    y[u] = s;
    }


    }
    for(int c= 0; c < y.length; c++){nums[c]= y[c];}
    return nums;} }

    ReplyDelete
  4. MichałDecember 20, 2016 at 10:13 AM

    public int[] fix34(int[] nums) {

    int temp = 0;
    boolean three = false;
    for (int i = 0; i < nums.length-1; i++)
    {
    if (nums[i] == 3)
    three = true;
    if (three == true)
    {
    three = false;
    if (nums[i+1] != 4)
    {
    for (int j = 1; j < nums.length; j++)
    {
    if (nums[j] == 4 && nums[j-1] != 3)
    {
    temp = nums[i+1];
    nums[i+1] = nums[j];
    nums[j] = temp;
    }
    }
    }
    }

    }

    return nums;
    }

    ReplyDelete
  5. AnonymousJanuary 23, 2017 at 7:37 AM

    public int[] fix34(int[] nums) {
    int[] vec4 = new int[10];
    int idxV4 = 0;
    //find all position where '4' stay
    for(int i = 0; i < nums.length; i++) {
    if(nums[i] == 4)
    vec4[idxV4++] = i;
    }
    int st4 = 0;
    //swap elenments 2 position before '3' and current '4'
    for(int i = 0; i < nums.length; i++) {
    if(i < nums.length - 1 && nums[i] == 3) {
    if(st4 <= idxV4){
    int temp = nums[i+1];
    nums[i+1] = nums[vec4[st4]];
    nums[vec4[st4]] = temp;
    st4++;
    }
    }
    }
    return nums;
    }

    ReplyDelete
  6. nh2March 13, 2017 at 11:19 AM

    public int[] fix34(int[] nums) {
    int pos4 = 1; // will hold the position of the next 4 (can't be < 1)
    for (int i=0 ; i<nums.length-1; ++i)
    if (nums[i]==3){
    while (nums[pos4]!=4) // search for the next 4
    pos4++;
    nums[pos4]=nums[++i];
    nums[i]=4;
    }
    return nums; // no need to return another array
    }

    ReplyDelete
  7. JavaAptechMarch 23, 2017 at 7:42 PM

    public int[] fix34(int[] nums) {
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    for (int j = 0; j < nums.length; j++) {
    if (nums[j] == 4) {
    if (j > 0 && nums[j-1] != 3) {
    int tmp = nums[i+1];
    nums[i+1] = 4;
    nums[j] = tmp;
    }
    else if (j == 0) {
    int tmp = nums[i+1];
    nums[i+1] = 4;
    nums[j] = tmp;
    }
    }
    }
    }
    }
    return nums;

    }





    ReplyDelete
  8. JavaAptechMarch 23, 2017 at 7:42 PM

    public int[] fix34(int[] nums) {
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    for (int j = 0; j < nums.length; j++) {
    if (nums[j] == 4) {
    if (j > 0 && nums[j-1] != 3) {
    int tmp = nums[i+1];
    nums[i+1] = 4;
    nums[j] = tmp;
    }
    else if (j == 0) {
    int tmp = nums[i+1];
    nums[i+1] = 4;
    nums[j] = tmp;
    }
    }
    }
    }
    }
    return nums;

    }





    ReplyDelete
  9. UnknownApril 11, 2017 at 6:58 AM

    int[] fix34(int[] nums) {
    int len = nums.length;
    boolean three = false;
    boolean four = false;

    for (int i = 0; i < len; i++) {
    if (nums[i] == 4) {
    four = true;
    }
    if (nums[i] == 3) {
    three = true;
    }
    for (int j = i+1; j < len; j++) {
    if (!four && !three) break;
    if (three && nums[j] == 4) {
    //replace
    nums[j] = nums[i + 1];
    nums[i + 1] = 4;
    three = false;
    i++;
    break;
    }
    if (four && nums[j] == 3 && nums[j + 1] != 4) {
    nums[i] = nums[j + 1];
    nums[j + 1] = 4;
    four = false;
    break;
    }
    }

    }
    return nums;
    }

    ReplyDelete
  10. UnknownAugust 1, 2017 at 2:35 AM

    public int[] fix34(int[] nums) {

    for(int i=0; i<nums.length-1; i++){
    if(nums[i] == 3){
    for(int j = 1; j<nums.length; j++){
    if(nums[j] == 4 && nums[j-1] != 3){
    int temp = nums[i+1];
    nums[i+1] = nums[j];
    nums[j] = temp;
    }
    }
    }
    }

    return nums;
    }

    ReplyDelete
  11. UnknownJanuary 1, 2018 at 11:19 PM

    public int[] fix34(int[] nums) {
    int val =0, lastF = 0;
    for (int i =0; i < nums.length; i++)
    if (nums[i] == 3){
    for (int j = 0; j < nums.length; j++)
    if (nums[j] == 4 && j >lastF){
    lastF =j;
    val = nums[i+1];
    nums[i+1] = nums[j];
    nums[j] = val;
    break;
    }
    }
    return nums;
    }

    ReplyDelete
  12. saketFebruary 20, 2019 at 1:05 PM

    def fix34(array):
    store = []
    for i in range(0, len(array)):
    if array[i] == 4:
    store.append(i)
    store.reverse()
    for i in range(0, len(array)):
    if array[i] == 3:
    index = store.pop()
    array[i + 1], array[index] = array[index], array[i + 1]
    return array

    assert fix34([1, 3, 1, 4]) == [1, 3, 4, 1]
    assert fix34([1, 3, 1, 4, 4, 3, 1]) == [1, 3, 4, 1, 1, 3, 4]
    assert fix34([3, 2, 2, 4]) == [3, 4, 2, 2]

    ReplyDelete
    Replies
    1. OutplayerOctober 12, 2021 at 10:37 AM

      def fix34(n):
      tmp = 0
      for i in range(len(n)):
      if n[i] == 3:
      for j in range( len(n)):
      if n[j] == 4 and n[j-1] != 3:
      tmp = n[i+1]
      n[i+1] = n[j]
      n[j] = tmp
      break
      return n

      Delete
  13. melonimeesMay 27, 2019 at 5:00 AM

    public int[] fix34(int[] nums) {
    // make temp for 4 and for number after 3 if not 4
    // check every number in array
    // if number after 3 is not 4 save it into temp
    // if found 4 that is not after 3 save it into temp4
    // if temp and temp4 are full, swap the values and make them 0;
    boolean tempFull = false;
    boolean temp4Full = false;

    int temp = 0;
    int tempIndex = 0;
    int temp4 = 0;
    int temp4Index = 0;

    for(int j=0; j<nums.length;j++){
    for(int i=0; i<nums.length;i++){
    if(nums[i] == 3 && nums[i+1]!=4){
    temp = nums[i+1];
    tempIndex = i+1;
    tempFull = true;
    } else if(nums[i] == 4 && nums[i-1]!=3){
    temp4 = nums[i];
    temp4Index = i;
    temp4Full = true;
    }
    if(temp4Full && tempFull){
    nums[tempIndex] = temp4;
    nums[temp4Index] = temp;
    tempFull = false;
    temp4Full = false;
    }
    }
    }
    return nums;
    }

    ReplyDelete
  14. lakohotJune 25, 2019 at 12:20 AM

    public int[] fix34(int[] nums) {
    int lastPlaceOf4 = 0;

    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    for (int j = lastPlaceOf4 ; j < nums.length; j++) {
    if (nums[j] == 4) {
    if(nums[j] == nums[i+1]) break;
    nums[i+1] = nums[i+1]^nums[j];
    nums[j] = nums[j]^nums[i+1];
    nums[i+1] = nums[i+1]^nums[j];
    lastPlaceOf4 = j;
    break;
    }
    }
    }
    }
    return nums;
    }

    ReplyDelete
  15. UnknownAugust 6, 2019 at 4:25 AM

    public int[] fix34(int[] nums) {
    for (int i = 0; i < nums.length-1; i++) {
    if(nums[i]==3 && nums[i+1]!=4) {
    for (int j = 0; j < nums.length; j++) {
    if(nums[j]==4 && nums[j-1]!=3) {
    int tmp= nums[i+1];
    nums[i+1]=nums[j];
    nums[j]=tmp;
    break;
    }
    }
    }
    }
    return nums;
    }

    ReplyDelete
  16. kvNovember 16, 2019 at 1:52 PM

    int idx=0;
    int tmp;
    for (int i = 0; i < nums.length; i++){
    if ((nums[i]==3)&&(nums[i+1]!=4)){
    //replace next number with first available 4
    for(int j = idx; j<nums.length; j++ ){
    if((nums[j]==4) && (nums[j-1]!=3)){
    tmp = nums[i+1];
    nums[i+1]=4;
    nums[j]=tmp;
    idx++;
    break;
    }

    }

    }
    }

    return nums;

    ReplyDelete
  17. LearningCodingApril 22, 2020 at 7:27 PM

    public int[] fix34(int[] nums) {
    int[] n = new int[nums.length];
    int temp = 0;
    int k =0;
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    for (int j = k; j < nums.length; j++) {
    if (nums[j] == 4) {
    temp = nums[i + 1];
    nums[i + 1] = nums[j];
    nums[j] = temp;
    k=j;
    break;
    }

    }

    }
    }

    return nums;
    }

    ReplyDelete
  18. UnknownJune 23, 2020 at 6:36 AM

    public int[] fix34(int[] nums) {
    int temp [] = new int [nums.length];
    if(nums.length==0) return temp;

    int j =0;
    for(int i=0; i< nums.length; i++){
    if(nums[i]==3){
    temp[i]=3;
    temp[i+1]=4;
    }
    }
    j=0;

    for(int i=0; i< temp.length; i++){
    if(nums[j]==4||nums[j]==3){
    j++;
    i--;
    }
    else if(temp[i]==4||temp[i]==3){

    }
    else {
    temp[i]=nums[j];
    }
    }

    return temp;
    }

    ReplyDelete
  19. ZeroJuly 12, 2020 at 9:10 PM

    public int[] fix34(int[] nums) {
    int arr[] = new int[nums.length];
    int tmp = 0;
    for(int x:nums){
    if(x != 3 && x != 4) tmp = x;
    }
    for(int i = 0; i < nums.length;i++){
    if(nums[i] == 3){
    arr[i] = 3;
    arr[i+1] = 4;
    i++;
    }else{
    arr[i] = tmp;
    }
    }
    return arr;
    }

    ReplyDelete
  20. UnknownJuly 16, 2020 at 9:30 AM

    public int[] fix34(int[] nums) {


    for(int i=0;i<nums.length;i++){
    if(nums[i]==3){
    for(int j=0;j<nums.length;j++){
    if(nums[j]==4 && nums[j-1]!=3){
    nums[j]=nums[i+1];
    nums[i+1]=4;

    }
    }
    }
    }

    return nums;
    }

    ReplyDelete
  21. UnknownJuly 17, 2020 at 3:40 PM

    public int[] fix34(int[] nums) {
    for (int i = 0; i < nums.length; i++)
    {
    if (nums[i] == 3)
    {
    for (int j = 1; j < nums.length; j++)
    {
    if (nums[j] == 4 && nums[j-1] != 3)
    {
    int temp = nums[i + 1];
    nums[i + 1] = nums[j];
    nums[j] = temp;
    break;
    }
    }
    }
    }
    return nums;
    }

    ReplyDelete
  22. UnknownAugust 13, 2020 at 1:17 PM

    public int[] fix34(int[] nums) {
    int j = 1;
    for (int i = 0; i < nums.length - 1; i++)
    {
    if (nums[i] == 3)
    {
    while (nums[j] != 4)
    {
    j++;
    }
    nums[j] = nums[i + 1];
    nums[i + 1] = 4;
    j++;
    }
    }
    return nums;
    }

    ReplyDelete
  23. UnknownSeptember 25, 2021 at 4:50 AM

    public int[] fix34(int[] nums) {

    for( int i = 0 ; i < nums.length; i++){
    if ( nums[i] == 3 && nums[i+1] != 4){
    int res = nums[i+1];
    nums[i+1] = 4;
    int j = 0 ;
    while( j < nums.length && !( nums[j] == 4 && nums[j-1]!=3) ){
    j++;
    }
    nums[j] = res;
    }

    }
    return nums;
    }

    ReplyDelete
  24. UnknownSeptember 29, 2021 at 9:07 PM

    public int[] fix34(int[] nums) {
    int sx;
    int ex;
    int l=nums.length;
    int[] ar=new int[l];

    for (int i=0; i<l ; i++){
    if (nums[i]==3) {
    ar[i]=3;
    ar[i+1]=4;
    }
    }

    for (int i=0; i<l ; i++){
    if (nums[i]!=3 && nums[i]!=4){
    for (int j=i; j<l ; j++){
    if (ar[j]!=3 && ar[j]!=4) ar[j]=nums[i];
    }
    }

    }

    return ar;

    }

    ReplyDelete
  25. UnknownDecember 31, 2021 at 7:06 PM

    I consider this one as cheating. There is an easy way if you use the fact that there is only one other individual number except 3 and 4.

    public int[] fix34(int[] nums) {
    int temp = 0;
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    temp = nums[i + 1];
    nums[i + 1] = 4;
    for (int j = 1; j < nums.length; j++) {
    if (nums[j - 1] != 3 && nums[j] == 4) {
    nums[j] = temp;
    }
    }
    }
    }
    return nums;
    }

    ReplyDelete
  26. UnknownJanuary 13, 2022 at 8:15 PM

    public int[] fix34(int[] nums) {
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3) {
    int index4 = 0;
    for (; index4 < nums.length; index4++) {
    if (nums[index4] == 3) {
    index4++; continue;
    }
    else if (nums[index4] == 4)break;
    }

    if (index4 == nums.length) break;
    nums[index4] = nums[i+1];
    nums[i+1] = 4;
    }
    }
    return nums;
    }

    ReplyDelete
  27. UnknownApril 3, 2022 at 6:27 AM

    public int[] fix34(int[] nums) {
    int tmp;
    for (int i = 0; i < nums.length; i++) {
    if (nums[i] == 3 && i != nums.length - 1) {
    i++;
    for (int j = 1; j < nums.length; j++) {
    if (nums[j] == 4 && nums[j-1] !=3) {
    tmp = nums[i];
    nums[i] = nums[j];
    nums[j] = tmp;
    }
    }
    }
    }
    return nums;
    }

    ReplyDelete
  28. PrasadDecember 12, 2022 at 7:57 AM

    public int[] fix34(int[] nums) {
    ArrayList ar3 = new ArrayList();
    ArrayList ar4 = new ArrayList();

    for(int i=0;i0) {
    ar4.add(i);
    } else if(i>0 && nums[i-1] == 3 && nums[i] != 4) {
    ar3.add(i);
    }
    }

    for(int i=0;i<ar3.size();i++) {
    int t = nums[ar3.get(i)];
    nums[ar3.get(i)] = nums[ar4.get(i)];
    nums[ar4.get(i)] = t;
    }
    return nums;
    }

    ReplyDelete

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