Permutations without repetition C












-1














I have this code for permutation WITH repetition. Would anyone help to modify it to be WITHOUT repetition. I can't figure it out.



int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
int array2[3];

void permWithRep (int array1, int array2, int last, int index){
int i, len = last+1;

enter code here
for ( i=0; i<len; i++ )
{
array2[index] = array1[i] ;

if (index == last){
for(int i = 0; i < 3; i++) {
printf("%d ", array2[i]);
}
printf("n");
}
else // Recur for higher indexes
permWithRep (array1, array2, last, index+1);
}
}

int main()
{
int len = sizeof(array1)/sizeof(int);
permWithRep (array1, array2, len-1, 0);
return 0;
}









share|improve this question
























  • Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
    – paddy
    Nov 12 '18 at 21:26










  • For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
    – Wumpus Q. Wumbley
    Nov 12 '18 at 21:49










  • What have you tried? What don't you understand about the problem?
    – chb
    Nov 12 '18 at 23:01
















-1














I have this code for permutation WITH repetition. Would anyone help to modify it to be WITHOUT repetition. I can't figure it out.



int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
int array2[3];

void permWithRep (int array1, int array2, int last, int index){
int i, len = last+1;

enter code here
for ( i=0; i<len; i++ )
{
array2[index] = array1[i] ;

if (index == last){
for(int i = 0; i < 3; i++) {
printf("%d ", array2[i]);
}
printf("n");
}
else // Recur for higher indexes
permWithRep (array1, array2, last, index+1);
}
}

int main()
{
int len = sizeof(array1)/sizeof(int);
permWithRep (array1, array2, len-1, 0);
return 0;
}









share|improve this question
























  • Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
    – paddy
    Nov 12 '18 at 21:26










  • For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
    – Wumpus Q. Wumbley
    Nov 12 '18 at 21:49










  • What have you tried? What don't you understand about the problem?
    – chb
    Nov 12 '18 at 23:01














-1












-1








-1







I have this code for permutation WITH repetition. Would anyone help to modify it to be WITHOUT repetition. I can't figure it out.



int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
int array2[3];

void permWithRep (int array1, int array2, int last, int index){
int i, len = last+1;

enter code here
for ( i=0; i<len; i++ )
{
array2[index] = array1[i] ;

if (index == last){
for(int i = 0; i < 3; i++) {
printf("%d ", array2[i]);
}
printf("n");
}
else // Recur for higher indexes
permWithRep (array1, array2, last, index+1);
}
}

int main()
{
int len = sizeof(array1)/sizeof(int);
permWithRep (array1, array2, len-1, 0);
return 0;
}









share|improve this question















I have this code for permutation WITH repetition. Would anyone help to modify it to be WITHOUT repetition. I can't figure it out.



int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
int array2[3];

void permWithRep (int array1, int array2, int last, int index){
int i, len = last+1;

enter code here
for ( i=0; i<len; i++ )
{
array2[index] = array1[i] ;

if (index == last){
for(int i = 0; i < 3; i++) {
printf("%d ", array2[i]);
}
printf("n");
}
else // Recur for higher indexes
permWithRep (array1, array2, last, index+1);
}
}

int main()
{
int len = sizeof(array1)/sizeof(int);
permWithRep (array1, array2, len-1, 0);
return 0;
}






c permutation repetition






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edited Nov 12 '18 at 22:01

























asked Nov 12 '18 at 21:19









Krivi21

82




82












  • Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
    – paddy
    Nov 12 '18 at 21:26










  • For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
    – Wumpus Q. Wumbley
    Nov 12 '18 at 21:49










  • What have you tried? What don't you understand about the problem?
    – chb
    Nov 12 '18 at 23:01


















  • Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
    – paddy
    Nov 12 '18 at 21:26










  • For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
    – Wumpus Q. Wumbley
    Nov 12 '18 at 21:49










  • What have you tried? What don't you understand about the problem?
    – chb
    Nov 12 '18 at 23:01
















Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
– paddy
Nov 12 '18 at 21:26




Would you define what you mean by "repetition"? That may sound like a strange question, but I do not see any repeated code. Perhaps you are talking about the loops. Do you want to remove all loops? Is this a homework exercise?
– paddy
Nov 12 '18 at 21:26












For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
– Wumpus Q. Wumbley
Nov 12 '18 at 21:49




For anyone unclear on the terminology of the question - en.wikipedia.org/wiki/Permutation#Permutations_with_repetition
– Wumpus Q. Wumbley
Nov 12 '18 at 21:49












What have you tried? What don't you understand about the problem?
– chb
Nov 12 '18 at 23:01




What have you tried? What don't you understand about the problem?
– chb
Nov 12 '18 at 23:01












1 Answer
1






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0














I tested this on few inputs and it works.

There is certainly a better way to do it, but that's what i did:



#include <stdio.h> 

int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
int array2[3];
int fixed[3];



void permWithRep(int array1, int array2,int fixed_index, int size , int level){

if(level == size) return print_array(array2,size);

for(int k = 0; k< size; k++){

if(!is_present_in_fixed(fixed_index,level,k)){
fixed_index[level] = k;
array2[level] = array1[k];
permWithRep(array1,array2,fixed_index,size,level+1);
}

}
}

void print_array(int array, int size){
for(int k = 0; k < size; k++)printf("%d ",array[k]);
printf("n");
}

int is_present_in_fixed(int array, int size, int element ){
for(int k =0; k<size;k++)
if(element == array[k]) return 1;
return 0;
}



int main()
{
int len = sizeof(array1)/sizeof(int);
permWithRep (array1, array2, fixed, len, 0);
return 0;
}


What I did:




  • Add an array (fixed_index) that keep track of the already visited indexes for one permutation.

  • In the loop, check if the index of current element belongs to the index already visited in that permutation (is_present_in_fixed(fixed_index,level,k)).

  • If so, it just skip that element (it does not enter the if statement).

  • Otherwise adds that element to the visited for that permutation and go on with recursive call.

  • When all array has been iterated on (level == size), just print the results contained in array2.






share|improve this answer





















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    1 Answer
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    1 Answer
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    active

    oldest

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    active

    oldest

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    0














    I tested this on few inputs and it works.

    There is certainly a better way to do it, but that's what i did:



    #include <stdio.h> 

    int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
    int array2[3];
    int fixed[3];



    void permWithRep(int array1, int array2,int fixed_index, int size , int level){

    if(level == size) return print_array(array2,size);

    for(int k = 0; k< size; k++){

    if(!is_present_in_fixed(fixed_index,level,k)){
    fixed_index[level] = k;
    array2[level] = array1[k];
    permWithRep(array1,array2,fixed_index,size,level+1);
    }

    }
    }

    void print_array(int array, int size){
    for(int k = 0; k < size; k++)printf("%d ",array[k]);
    printf("n");
    }

    int is_present_in_fixed(int array, int size, int element ){
    for(int k =0; k<size;k++)
    if(element == array[k]) return 1;
    return 0;
    }



    int main()
    {
    int len = sizeof(array1)/sizeof(int);
    permWithRep (array1, array2, fixed, len, 0);
    return 0;
    }


    What I did:




    • Add an array (fixed_index) that keep track of the already visited indexes for one permutation.

    • In the loop, check if the index of current element belongs to the index already visited in that permutation (is_present_in_fixed(fixed_index,level,k)).

    • If so, it just skip that element (it does not enter the if statement).

    • Otherwise adds that element to the visited for that permutation and go on with recursive call.

    • When all array has been iterated on (level == size), just print the results contained in array2.






    share|improve this answer


























      0














      I tested this on few inputs and it works.

      There is certainly a better way to do it, but that's what i did:



      #include <stdio.h> 

      int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
      int array2[3];
      int fixed[3];



      void permWithRep(int array1, int array2,int fixed_index, int size , int level){

      if(level == size) return print_array(array2,size);

      for(int k = 0; k< size; k++){

      if(!is_present_in_fixed(fixed_index,level,k)){
      fixed_index[level] = k;
      array2[level] = array1[k];
      permWithRep(array1,array2,fixed_index,size,level+1);
      }

      }
      }

      void print_array(int array, int size){
      for(int k = 0; k < size; k++)printf("%d ",array[k]);
      printf("n");
      }

      int is_present_in_fixed(int array, int size, int element ){
      for(int k =0; k<size;k++)
      if(element == array[k]) return 1;
      return 0;
      }



      int main()
      {
      int len = sizeof(array1)/sizeof(int);
      permWithRep (array1, array2, fixed, len, 0);
      return 0;
      }


      What I did:




      • Add an array (fixed_index) that keep track of the already visited indexes for one permutation.

      • In the loop, check if the index of current element belongs to the index already visited in that permutation (is_present_in_fixed(fixed_index,level,k)).

      • If so, it just skip that element (it does not enter the if statement).

      • Otherwise adds that element to the visited for that permutation and go on with recursive call.

      • When all array has been iterated on (level == size), just print the results contained in array2.






      share|improve this answer
























        0












        0








        0






        I tested this on few inputs and it works.

        There is certainly a better way to do it, but that's what i did:



        #include <stdio.h> 

        int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
        int array2[3];
        int fixed[3];



        void permWithRep(int array1, int array2,int fixed_index, int size , int level){

        if(level == size) return print_array(array2,size);

        for(int k = 0; k< size; k++){

        if(!is_present_in_fixed(fixed_index,level,k)){
        fixed_index[level] = k;
        array2[level] = array1[k];
        permWithRep(array1,array2,fixed_index,size,level+1);
        }

        }
        }

        void print_array(int array, int size){
        for(int k = 0; k < size; k++)printf("%d ",array[k]);
        printf("n");
        }

        int is_present_in_fixed(int array, int size, int element ){
        for(int k =0; k<size;k++)
        if(element == array[k]) return 1;
        return 0;
        }



        int main()
        {
        int len = sizeof(array1)/sizeof(int);
        permWithRep (array1, array2, fixed, len, 0);
        return 0;
        }


        What I did:




        • Add an array (fixed_index) that keep track of the already visited indexes for one permutation.

        • In the loop, check if the index of current element belongs to the index already visited in that permutation (is_present_in_fixed(fixed_index,level,k)).

        • If so, it just skip that element (it does not enter the if statement).

        • Otherwise adds that element to the visited for that permutation and go on with recursive call.

        • When all array has been iterated on (level == size), just print the results contained in array2.






        share|improve this answer












        I tested this on few inputs and it works.

        There is certainly a better way to do it, but that's what i did:



        #include <stdio.h> 

        int array1 = {1, 2, 3}; //array can be {1,1,2,3} for example also
        int array2[3];
        int fixed[3];



        void permWithRep(int array1, int array2,int fixed_index, int size , int level){

        if(level == size) return print_array(array2,size);

        for(int k = 0; k< size; k++){

        if(!is_present_in_fixed(fixed_index,level,k)){
        fixed_index[level] = k;
        array2[level] = array1[k];
        permWithRep(array1,array2,fixed_index,size,level+1);
        }

        }
        }

        void print_array(int array, int size){
        for(int k = 0; k < size; k++)printf("%d ",array[k]);
        printf("n");
        }

        int is_present_in_fixed(int array, int size, int element ){
        for(int k =0; k<size;k++)
        if(element == array[k]) return 1;
        return 0;
        }



        int main()
        {
        int len = sizeof(array1)/sizeof(int);
        permWithRep (array1, array2, fixed, len, 0);
        return 0;
        }


        What I did:




        • Add an array (fixed_index) that keep track of the already visited indexes for one permutation.

        • In the loop, check if the index of current element belongs to the index already visited in that permutation (is_present_in_fixed(fixed_index,level,k)).

        • If so, it just skip that element (it does not enter the if statement).

        • Otherwise adds that element to the visited for that permutation and go on with recursive call.

        • When all array has been iterated on (level == size), just print the results contained in array2.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 12 '18 at 23:05









        Ollaw

        940517




        940517






























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