add 3120

Author: fishercoder1534

README.md

@@ -9,7 +9,8 @@ _If you like this project, please leave me a star._ ★
 | #    |      Title     | Solutions                                                                                                                                | Video                                                                         | Difficulty                       | Tag                                                                  
 |------|----------------|------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------|----------------------------------|----------------------------------------------------------------------
 | 3131 |[Find the Integer Added to Array I](https://leetcode.com/problems/find-the-integer-added-to-array-i/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3131.java)                                                                     |                                           | Easy                             |
-| 3127 |[Make a Square with the Same Color](https://leetcode.com/problems/make-a-square-with-the-same-color/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3127.java)                                                                      |                                           | Easy                             |
+| 3127 |[Make a Square with the Same Color](https://leetcode.com/problems/make-a-square-with-the-same-color/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3127.java)                                                                     |                                           | Easy                             |
+| 3120 |[Count the Number of Special Characters I](https://leetcode.com/problems/count-the-number-of-special-characters-i/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3120.java)                                                                     |                                           | Easy                             |
 | 3046 |[Split the Array](https://leetcode.com/problems/split-the-array/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3046.java)                                                                     |                                           | Easy                             |
 | 3042 |[Count Prefix and Suffix Pairs I](https://leetcode.com/problems/count-prefix-and-suffix-pairs-i/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3042.java)                                                                     |                                           | Easy                             |
 | 3038 |[Maximum Number of Operations With the Same Score I](https://leetcode.com/problems/maximum-number-of-operations-with-the-same-score-i/)| [Java](../master/src/main/java/com/fishercoder/solutions/_3038.java)                                                                     |                                           | Easy                             |

src/main/java/com/fishercoder/solutions/_3120.java

@@ -0,0 +1,24 @@
+package com.fishercoder.solutions;
+
+public class _3120 {
+    public static class Solution1 {
+        public int numberOfSpecialChars(String word) {
+            int count = 0;
+            int[] lower = new int[26];
+            int[] upper = new int[26];
+            for (char c : word.toCharArray()) {
+                if (Character.isLowerCase(c)) {
+                    lower[c - 'a']++;
+                } else {
+                    upper[c - 'A']++;
+                }
+            }
+            for (int i = 0; i < 26; i++) {
+                if (lower[i] != 0 && upper[i] != 0) {
+                    count++;
+                }
+            }
+            return count;
+        }
+    }
+}