Check if the given Trie contains words starting from every alphabet
Given a Trie, the task is to check if it contains words starting from every alphabet from [a – z].
Examples:
Input: keys[] = {“element”, “fog”, “great”, “hi”,
“ok”, “ios”, “parrot”, “quiz”, “kim”, “mango”, “nature”, “apple”,
“ball”, “cat”, “dog”, “lime”, “ruby”, “shine”, “tinkter”,
“ultra”, “volly”, “wow”, “xerox”, “yak”, “zenon”, “joke”}
Output: YesInput: keys[] = {“geeks”, “for”, “geeks”}
Output: No
Approach: We just need to focus on the root node of the given Trie and no need to traverse other nodes. We simply check if Trie has all its child pointers pointing to valid nodes i.e. there are words starting from every character of the alphabet.
Below is the implementation of the above approach:
// C++ implementation of the approach#include <bits/stdc++.h>using namespace std; const int ALPHABET_SIZE = 26; // Trie nodestruct TrieNode { struct TrieNode* children[ALPHABET_SIZE]; // isEndOfWord is true if the node represents // end of a word bool isEndOfWord;}; // Returns new trie node (initialized to NULL)struct TrieNode* getNode(void){ struct TrieNode* pNode = new TrieNode; pNode->isEndOfWord = false; for (int i = 0; i < ALPHABET_SIZE; i++) pNode->children[i] = NULL; return pNode;} // If not present, inserts key into trie// If the key is prefix of trie node, just// marks leaf nodevoid insert(struct TrieNode* root, string key){ struct TrieNode* pCrawl = root; for (int i = 0; i < key.length(); i++) { int index = key[i] - 'a'; if (!pCrawl->children[index]) pCrawl->children[index] = getNode(); pCrawl = pCrawl->children[index]; } // Mark last node as leaf pCrawl->isEndOfWord = true;} // Function to check if Trie contains words// starting from all the alphabetsbool containsAll(TrieNode* root){ // We check if root node has all childs // if None of them is NULL then we return true for (int i = 0; i < 26; i++) { // If there is no word in the trie starting // from the current alphabet if (root->children[i] == NULL) return false; } return true;} // Driver codeint main(){ string keys[] = { "element", "fog", "great", "hi", "ok", "ios", "parrot", "quiz", "kim", "mango", "nature", "apple", "ball", "cat", "dog", "lime", "ruby", "shine", "tinkter", "ultra", "volly", "wow", "xerox", "yak", "zenon", "joke" }; int n = sizeof(keys) / sizeof(keys[0]); // Create the Trie struct TrieNode* root = getNode(); for (int i = 0; i < n; i++) insert(root, keys[i]); // If trie contains words starting // from every alphabet if (containsAll(root)) cout << "Yes"; else cout << "No"; return 0;} |
Yes
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please refer Complete Interview Preparation Course.
In case you wish to attend live classes with experts, please refer DSA Live Classes for Working Professionals and Competitive Programming Live for Students.
