add 2109

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                  
 |-----|----------------|---------------|--------|-------------|-------------
+|2109|[Adding Spaces to a String](https://leetcode.com/problems/adding-spaces-to-a-string/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2109.java) ||Medium||
 |2108|[Find First Palindromic String in the Array](https://leetcode.com/problems/find-first-palindromic-string-in-the-array/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2108.java) ||Easy||
 |2103|[Rings and Rods](https://leetcode.com/problems/rings-and-rods/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2103.java) ||Easy||
 |2099|[Find Subsequence of Length K With the Largest Sum](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2099.java) ||Easy||

src/main/java/com/fishercoder/solutions/_2109.java

@@ -0,0 +1,17 @@
+package com.fishercoder.solutions;
+
+public class _2109 {
+    public static class Solution1 {
+        public String addSpaces(String s, int[] spaces) {
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0, j = 0; i < s.length(); i++) {
+                if (j < spaces.length && i == spaces[j]) {
+                    sb.append(" ");
+                    j++;
+                }
+                sb.append(s.charAt(i));
+            }
+            return sb.toString();
+        }
+    }
+}