feat: 2138

Author: Alonza0314

docs/Easy/2138 Divide a String Into Groups of Size k.md

@@ -0,0 +1,45 @@
+# 2138. Divide a String Into Groups of Size k
+
+## Intuition
+
+The problem requires dividing a string into groups of size k. If the last group has fewer characters than k, we need to fill it with the given fill character until it reaches size k. This suggests using a loop to process the string in chunks of k characters.
+
+## Approach
+
+1. Create an empty slice to store the resulting strings
+2. Iterate through the string with steps of k characters
+3. For each iteration:
+    - If there are at least k characters remaining, take a substring of k characters
+    - If there are fewer than k characters remaining:
+        - Take the remaining characters
+        - Fill the rest with the given fill character until reaching length k
+4. Return the resulting slice of strings
+
+## Complexity
+
+- Time complexity: O(n)
+- Space complexity: O(n)
+
+## Keywords
+
+- String Manipulation
+- String Padding
+
+## Code
+
+```go
+func divideString(s string, k int, fill byte) []string {
+    ret := make([]string, 0)
+    for i := 0; i < len(s); i += k {
+        if i + k < len(s) {
+            ret = append(ret, string(s[i: i + k]))
+        } else {
+            ret = append(ret, string(s[i:]))
+            for j := len(ret[len(ret) - 1]); j < k; j += 1 {
+                ret[len(ret) - 1] += string(fill)
+            } 
+        }
+    }
+    return ret
+}
+```

docs/index.md

@@ -77,6 +77,7 @@
 | 1395 | Count Number of Trams | [go](Medium/1395%20Count%20Number%20of%20Teams.md) | M |
 | 2016 | Maximum Difference Between Increasing Elements | [go](Easy/2016%20Maximum%20Difference%20Between%20Increasing%20Elements.md) | E |
 | 2071 | Maximum Number of Tasks You Can Assign | [go](Hard/2071%20Maximum%20Number%20of%20Tasks%20You%20Can%20Assign.md) | H |
+| 2138 | Divide a String Into Groups of Size k | [go](Easy/2138%20Divide%20a%20String%20Into%20Groups%20of%20Size%20k.md) | E |
 | 2294 | Partition Array Such That Maximum Difference Is K | [go](Medium/2294%20Partition%20Array%20Such%20That%20Maximum%20Difference%20Is%20K.md) | M |
 | 2366 | Mimimum Replacements to Sort the Array | [go](Hard/2366%20Minimum%20Replacements%20to%20Sort%20the%20Array.md) | H |
 | 2392 | Build A Matrix with Conditions | [go](Hard/2392%20Build%20A%20Matrix%20With%20Conditions.md) | H |