Merge branch 'sudoku_improvement' of https://github.com/Hardvan/Java into sudoku_improvement

Author: Hardvan

DIRECTORY.md

@@ -892,7 +892,6 @@
             * [ReturnSubsequenceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReturnSubsequenceTest.java)
             * [ReverseStackUsingRecursionTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java)
             * [StringMatchFiniteAutomataTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/StringMatchFiniteAutomataTest.java)
-            * [SudokuTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/SudokuTest.java)
             * [TestPrintMatrixInSpiralOrder](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TestPrintMatrixInSpiralOrder.java)
             * [TwoPointersTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/TwoPointersTest.java)
             * [WorstFitCPUTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/others/WorstFitCPUTest.java)