Merge pull request #1923 from Hemav009/395

Added 395

Author: ajay-dhangar

dsa-solutions/lc-solutions/0300-0399/0389-find-the-difference.md

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+---
+id: Find the Difference
+title: Find the Difference
+sidebar_label: 0389-Find the Difference
+tags:
+  - Leet code
+description: "Solution to leetocde 389"
+---
+
+### Problem Description
+
+You are given two strings s and t.
+
+String t is generated by random shuffling string s and then add one more letter at a random position.
+
+Return the letter that was added to t.
+
+Example 1:
+
+```
+Input: s = "abcd", t = "abcde"
+Output: "e"
+Explanation: 'e' is the letter that was added.
+```
+
+Example 2:
+
+```
+Input: s = "", t = "y"
+Output: "y"
+```
+
+### Constraints:
+
+- $0 <= s.length <= 1000$
+- $t.length == s.length + 1$
+- $s and t consist of lowercase English letters.$
+
+### Algorithm
+
+1. For each character i in t, it checks if the count of i in t is greater than the count of i in s. If this condition is met, it means that i is the extra letter that was added to t, so it returns i and breaks out of the loop.
+
+### Code Implementation
+
+**Python:**
+
+```python
+class Solution(object):
+  def findTheDifference(self, s, t):
+    for char in t:
+      if t.count(char) > s.count(char):
+        return char
+```
+
+**C++:**
+
+```c++
+#include <unordered_map>
+
+char findTheDifference(std::string s, std::string t) {
+  std::unordered_map<char, int> char_counts;
+  for (char c : s) {
+    char_counts[c]++;
+  }
+  for (char c : t) {
+    if (char_counts.find(c) == char_counts.end() || char_counts[c] == 0) {
+      return c;
+    }
+    char_counts[c]--;
+  }
+  return '\0'; // Return null character if no difference found
+}
+```
+
+**Java:**
+
+```java
+public class Solution {
+  public char findTheDifference(String s, String t) {
+    HashMap<Character, Integer> char_counts = new HashMap<>();
+    for (char c : s.toCharArray()) {
+      char_counts.put(c, char_counts.getOrDefault(c, 0) + 1);
+    }
+    for (char c : t.toCharArray()) {
+      if (!char_counts.containsKey(c) || char_counts.get(c) == 0) {
+        return c;
+      }
+      char_counts.put(c, char_counts.get(c) - 1);
+    }
+    return '\u0000'; // Return null character if no difference found (Unicode representation)
+  }
+}
+```
+
+**JavaScript:**
+
+```javascript
+function findTheDifference(s, t) {
+  const char_counts = {};
+  for (const char of s) {
+    char_counts[char] = (char_counts[char] || 0) + 1;
+  }
+  for (const char of t) {
+    if (!(char in char_counts) || char_counts[char] === 0) {
+      return char;
+    }
+    char_counts[char]--;
+  }
+  return ""; // Return empty string if no difference found
+}
+```