Create 2138-divide-a-string-into-groups-of-size-k.java

Author: sanajitjana

Easy/2138-divide-a-string-into-groups-of-size-k.java

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+/*
+Problem: Divide a String Into Groups of Size k
+LeetCode: https://leetcode.com/problems/divide-a-string-into-groups-of-size-k/
+
+Given a string s, divide the string into groups of size k (except for the last group, which may be shorter). 
+If the last group is shorter than k, fill it with the character fill.
+
+Approach:
+- Calculate the number of resulting groups based on the string length and k.
+- Iterate over the string in steps of k.
+- For each group, build a substring of length k.
+    - If characters run out, append the fill character.
+- Store each group in the result array and return it.
+
+Time Complexity: O(n) where n is the length of string s.
+Space Complexity: O(n) for storing the resulting array of strings.
+*/
+
+class Solution {
+    public String[] divideString(String s, int k, char fill) {
+        int sLen = s.length();
+        int aLen = sLen % k == 0 ? sLen / k : sLen / k + 1;
+        String[] str = new String[aLen];
+
+        int index = 0;
+        for (int i = 0; i < sLen; i += k) {
+            StringBuilder sb = new StringBuilder();
+            for (int j = i; j < k + i; j++) {
+                if (j < sLen) {
+                    sb.append(s.charAt(j));
+                } else {
+                    sb.append(fill);
+                }
+            }
+            str[index++] = sb.toString();
+        }
+        return str;
+    }
+}