java - all possible combination of n sets -


i have n sets. each set has different number of elements. write algorithm give me possible combinations sets. example: lets have:

s1={1,2}, s2={a,b,c}, s3={$,%,£,!}

a combination should like

c1={1,a,$} c2={1,a,%}

.... , on number of possible combination 2*3*4 = 24

please me write algorithm in java.

many in advance

recursion friend:

public class printsetcomb{     public static void main(string[] args){         string[] set1 = {"1","2"};         string[] set2 = {"a","b","c"};         string[] set3 = {"$", "%", "£", "!"};         string[][] sets = {set1, set2, set3};          printcombinations(sets, 0, "");     }      private static void printcombinations(string[][] sets, int n, string prefix){         if(n >= sets.length){             system.out.println("{"+prefix.substring(0,prefix.length()-1)+"}");             return;         }         for(string s : sets[n]){             printcombinations(sets, n+1, prefix+s+",");         }     } }

in response question op generalizing sets of objects:

import java.util.arrays;  public class printsetcomb{      public static void main(string[] args){         integer[] set1  = {1,2};         float[] set2    = {2.0f,1.3f,2.8f};         string[] set3   = {"$", "%", "£", "!"};         object[][] sets = {set1, set2, set3};          printcombinations(sets, 0, new object[0]);     }      private static void printcombinations(object[][] sets, int n, object[] prefix){         if(n >= sets.length){             string outp = "{";             for(object o: prefix){                 outp = outp+o.tostring()+",";             }             system.out.println(outp.substring(0,outp.length()-1)+"}");             return;         }         for(object o : sets[n]){             object[] newprefix = arrays.copyofrange(prefix,0,prefix.length+1);             newprefix[newprefix.length-1] = o;             printcombinations(sets, n+1, newprefix);         }     } }

and iterative variant. based on increasing array of counters counter wraps , carries when reaches size of set:

import java.util.arrays;  public class printsetcombiterative{      public static void main(string[] args){             string[] set1 = {"1","2"};             string[] set2 = {"a","b","c"};             string[] set3 = {"$", "%", "£", "!"};             object[][] sets = {set1, set2, set3};              printcombinations(sets);     }       private static void printcombinations(object[][] sets){         int[] counters = new int[sets.length];          do{            system.out.println(getcombinationstring(counters, sets));         }while(increment(counters, sets));     }      private static boolean increment(int[] counters, object[][] sets){             for(int i=counters.length-1;i>=0;i--){                 if(counters[i] < sets[i].length-1){                     counters[i]++;                     return true;                 } else {                     counters[i] = 0;                 }             }             return false;     }      private static string getcombinationstring(int[] counters, object[][] sets){         string combo = "{";         for(int = 0; i<counters.length;i++){             combo = combo+sets[i][counters[i]]+",";         }         return combo.substring(0,combo.length()-1)+"}";      } }

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