Finding repeated words on a string and counting the repetitions

Question

I need to find repeated words on a string, and then count how many times they were repeated. So basically, if the input string is this:

String s = \"House, House         


        

Answer 1

You can use Prefix tree (trie) data structure to store words and keep track of count of words within Prefix Tree Node.

  #define  ALPHABET_SIZE 26
  // Structure of each node of prefix tree
  struct prefix_tree_node {
    prefix_tree_node() : count(0) {}
    int count;
    prefix_tree_node *child[ALPHABET_SIZE];
  };
  void insert_string_in_prefix_tree(string word)
  {
    prefix_tree_node *current = root;
    for(unsigned int i=0;i(word[i] - 'a');

      // Invalid alphabetic character, then continue
      // Note :::: Change this condition depending on the scenario
      if(letter > 26)
        throw runtime_error("Invalid alphabetic character");

      if(current->child[letter] == NULL)
        current->child[letter] = new prefix_tree_node();

      current = current->child[letter];
    }
  current->count++;
  // Insert this string into Max Heap and sort them by counts
}

    // Data structure for storing in Heap will be something like this
    struct MaxHeapNode {
       int count;
       string word;
    };

After inserting all words, you have to print word and count by iterating Maxheap.