solves #3216: Lexicographically Smallest String After a Swap in java

Author: anishLearnsToCode

README.md

@@ -926,6 +926,6 @@
 | 3200 | [Maximum Height of a Triangle](https://leetcode.com/problems/maximum-height-of-a-triangle)                                                                             |                                                                                  [![Java](assets/java.png)](src/MaximumHeightOfATriangle.java)                                                                                   |                                                                                                                                   |
 | 3206 | [Alternating Groups I](https://leetcode.com/problems/alternating-groups-i)                                                                                             |                                                                                     [![Java](assets/java.png)](src/AlternatingGroupsI.java)                                                                                      |                                                                                                                                   |
 | 3210 | [Find the Encrypted String](https://leetcode.com/problems/find-the-encrypted-string)                                                                                   |                                                                                   [![Java](assets/java.png)](src/FindTheEncryptedString.java)                                                                                    |                                                                                                                                   |
-| 3216 | [Lexicographically Smallest String After a Swap](https://leetcode.com/problems/lexicographically-smallest-string-after-a-swap)                                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 3216 | [Lexicographically Smallest String After a Swap](https://leetcode.com/problems/lexicographically-smallest-string-after-a-swap)                                         |                                                                          [![Java](assets/java.png)](src/LexicographicallySmallestStringAfterASwap.java)                                                                          |                                                                                                                                   |
 | 3222 | [Find the Winning Player in Coin Game](https://leetcode.com/problems/find-the-winning-player-in-coin-game)                                                             |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 3226 | [Number of Bit Changes to Make Two Integers Equal](https://leetcode.com/problems/number-of-bit-changes-to-make-two-integers-equal)                                     |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/LexicographicallySmallestStringAfterASwap.java

@@ -0,0 +1,24 @@
+// https://leetcode.com/problems/lexicographically-smallest-string-after-a-swap
+// T: O(|s|)
+// S: O(|s|)
+
+public class LexicographicallySmallestStringAfterASwap {
+    public String getSmallestString(String s) {
+        for (int i = 0 ; i < s.length() - 1 ; i++) {
+            if (sameParity(s, i) && s.charAt(i) > s.charAt(i + 1)) {
+                return swapCharWithNextChar(s, i);
+            }
+        }
+        return s;
+    }
+
+    private static boolean sameParity(String s, int index) {
+        return Integer.parseInt(s.charAt(index) + "") % 2 ==
+                Integer.parseInt(s.charAt(index + 1) + "") % 2;
+    }
+
+    private static String swapCharWithNextChar(String s, int index) {
+        return s.substring(0, index) + s.charAt(index + 1)
+                + s.charAt(index) + s.substring(index + 2);
+    }
+}