CODEWITHSUNDEEP
javaandroid
Mark
Mark

Reputation: 1400

Generating ordered permutations of a given string

Given a sentence like "one two three four" how would I iterate the List of words in ordered permutation?

This is what I'm trying to achieve

"one"
"one two"
"one two three"
"one two three four"
"two"
"two three"
"two three four"
"three"
"three four"
"four"

I've split the words using space delimiter but cannot work out a method to iterate all the combinations with words kept in current order.

  List<String> product_words = new ArrayList<String>(Arrays.asList(productname.split(" ")));
  for (int x = 0; x < product_words.size(); x++) { 
        //stuck here
  }

Thanks in advance

Upvotes: 0

Views: 661

Answers (1)

Tyler
Tyler

Reputation: 18177

All you need is a double for loop, and make sure to start the inner loop at the index of the outer loop (that will omit "one", after you've gone through all of its permutations).

ArrayList<String> product_words = new ArrayList<String>();
product_words.add("one");
product_words.add("two");
product_words.add("three");
product_words.add("four");

for (int i = 0; i < product_words.size(); i++) {
    String s = "";
    for (int j = i; j < product_words.size(); j++)  {
        s += product_words.get(j);
        s += " ";
        System.out.println(s);
    }
}

Upvotes: 2

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