Camelcase Matching in C++

Suppose we have a list of queries, and a pattern, we have to return an answer that will be list of booleans, where answer[i] is true if and only if queries[i] matches the pattern. A query word matches a given pattern when we can insert lowercase letters to the pattern word so that it equals the query.

So if the input is like ["FooBar","FooBarTest","FootBall","FrameBuffer","ForceFeedBack"] and pattern = "FB", then the results will be [true,false,true,false,false].

To solve this, we will follow these steps −

• Define a method called insertNode(), this takes head and string s

• curr := head

• for i in range 0 to size of s – 1

  • x := s[i]

  • if child[x] of curr is not null, then child[x] of curr := new node

  • curr := child[x] of curr

• set isEnd of curr := true

• From the main method, do the following −

• head := new node, insert pattern into head, n := size of query array, m := size of temp, ok := true

• for j in range 0 to m – 1

  • x := temp[j]

  • if child[x] of curr, then curr := child[x] of curr

  • otherwise when temp[j] is in range A to Z, then ok := false and break from loop

  • ans[i] := isEnd of curr AND ok

• return ans

Example(C++)

Let us see the following implementation to get a better understanding −

 Live Demo

#include <bits/stdc++.h>
using namespace std;
void print_vector(vector<auto> v){
   cout << "[";
   for(int i = 0; i<v.size(); i++){
      cout << v[i] << ", ";
   }
   cout << "]"<<endl;
}
struct Node{
   bool isEnd;
   map <char, Node*> child;
   Node(){
      isEnd = false;
   }
};
class Solution {
   public:
   void insertNode(Node* head, string s){
      Node* curr = head;
      for(int i = 0; i < s.size(); i++){
         char x = s[i];
         if(!curr->child[x]){
            curr->child[x] = new Node();
         }
         curr = curr->child[x];
      }
      curr->isEnd = true;
   }
   vector<bool> camelMatch(vector<string>& queries, string pattern){
      Node* head = new Node();
      insertNode(head, pattern);
      int n = queries.size();
      vector <bool> ans(n);
      Node* curr;
      bool ok;
      for(int i = 0; i < n; i++){
         string temp = queries[i];
         curr = head;
         int m = temp.size();
         ok = true;
         for(int j = 0; j < m; j++){
            char x = temp[j];
            if(curr->child[x]){
               curr = curr->child[x];
            }
            else if(temp[j] >= 'A' && temp[j] <= 'Z'){
               ok = false;
               break;
            }
         }
         ans[i] = curr->isEnd && ok;
      }
      return ans;
   }
};
main(){
   vector<string> v1 = {"FooBar","FooBarTest","FootBall","FrameBuffer","ForceFeedBack"};
   Solution ob;
   print_vector(ob.camelMatch(v1, "FB"));
}

Input

["FooBar","FooBarTest","FootBall","FrameBuffer","ForceFeedBack"]
"FB"

Output

[1, 0, 1, 1, 0, ]