Add trie implementation to find shortest unique prefix

Trie/shortestUniqPref.cpp

@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+using namespace std;
+/*
+    time complexity for Trie construction           -> O(n) -> n is total characters in words
+    finding character nearest to root with freq 1   -> O(n) -> n is total characters in words
+*/
+struct Trie
+{
+    Trie *child[26] = {NULL};
+    bool isLeaf = false;
+    int cnt = 1;
+};
+
+void insert(Trie *root, string s)
+{
+    int n = s.size();
+    for (int i = 0; i < n; i++)
+    {
+        int key = s[i] - 'a';
+        if (root->child[key] == NULL)
+        {
+            root->child[key] = new Trie;
+        }else{
+            (root->child[key]->cnt)++;
+        }
+        root = root->child[key];
+    }
+    root->isLeaf = true;
+}
+void findPref(Trie *root, string s, vector<string> &ans)
+{
+    if (root && root->cnt == 1)
+    {
+        ans.push_back(s);
+        return;
+    }
+    if (root == NULL)
+        return;
+    for (int i = 0; i < 26; i++)
+    {
+        if (root->child[i])
+        {
+            findPref(root->child[i], s + (char)(i + 'a'), ans);
+        }
+    }
+}
+int main()
+{
+    vector<string> v{"geeksgeeks", "geeksquiz", "geeksforgeeks"};
+    vector<string> ans;
+    int n = v.size();
+    Trie *root = new Trie;
+    for (int i = 0; i < n; i++)
+    {
+        insert(root, v[i]);
+    }
+    for (int i = 0; i < 26; i++)
+    {
+        string s = "";
+        if (root->child[i])
+        {
+            findPref(root->child[i], s + (char)(i + 'a'), ans);
+        }
+    }
+    for (auto x : ans)
+    {
+        cout << x << " ";
+    }
+    cout << endl;
+    return 0;
+}