solves reorder data in log files

Author: anishLearnsToCode

README.md

@@ -252,7 +252,7 @@
 | 925 | [Long Pressed Name](https://leetcode.com/problems/long-pressed-name) | [![Java](assets/java.png)](src/LongPressedName.java) |
 | 929 | [Unique Email Addresses](https://leetcode.com/problems/unique-email-addresses) | [![Java](assets/java.png)](src/UniqueEmailAddresses.java) |
 | 933 | [Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls) | [![Java](assets/java.png)](src/NumberOfRecentCalls.java) |
-| 937 | [Reorder Data In Log Files](https://leetcode.com/problems/reorder-data-in-log-files) | |
+| 937 | [Reorder Data In Log Files](https://leetcode.com/problems/reorder-data-in-log-files) | [![Java](assets/java.png)](src/ReorderDataInLogFiles.java) |
 | 938 | [Range Sum of BST](https://leetcode.com/problems/range-sum-of-bst) | |
 | 941 | [Valid Mountain Array](https://leetcode.com/problems/valid-mountain-array) | |
 | 942 | [DI String Match](https://leetcode.com/problems/di-string-match) | |

src/ReorderDataInLogFiles.java

@@ -0,0 +1,33 @@
+import java.util.Arrays;
+
+public class ReorderDataInLogFiles {
+    public String[] reorderLogFiles(String[] logs) {
+        Arrays.sort(logs, (log1, log2) -> {
+            String[] split1 = log1.split(" ", 2);
+            String[] split2 = log2.split(" ", 2);
+
+            boolean isDigit1 = Character.isDigit(split1[1].charAt(0));
+            boolean isDigit2 = Character.isDigit(split2[1].charAt(0));
+
+            // case 1). both logs are letter-logs
+            if (!isDigit1 && !isDigit2) {
+                // first compare the content
+                int cmp = split1[1].compareTo(split2[1]);
+                if (cmp != 0) return cmp;
+                // logs of same content, compare the identifiers
+                return split1[0].compareTo(split2[0]);
+            }
+
+            // case 2). one of logs is digit-log
+            if (!isDigit1)
+                // the letter-log comes before digit-logs
+                return -1;
+            else if (!isDigit2)
+                return 1;
+            else
+                // case 3). both logs are digit-log
+                return 0;
+        });
+        return logs;
+    }
+}