@Test
 public void test2() {
   Solution_2 sol = new KthSmallestElementinaSortedMatrix().new Solution_2();
   int[][] matrix = {
     {1, 5, 9},
     {10, 11, 13},
     {12, 13, 15}
   };
   assertEquals(1, sol.kthSmallest(matrix, 1));
   assertEquals(9, sol.kthSmallest(matrix, 3));
   assertEquals(11, sol.kthSmallest(matrix, 5));
   assertEquals(12, sol.kthSmallest(matrix, 6));
   assertEquals(13, sol.kthSmallest(matrix, 7));
   assertEquals(13, sol.kthSmallest(matrix, 8));
   assertEquals(15, sol.kthSmallest(matrix, 9));
 }
 @Test
 public void test2() {
   Solution_2 sol = new IntegerBreak().new Solution_2();
   assertEquals(1, sol.integerBreak(2));
   assertEquals(2, sol.integerBreak(3));
   assertEquals(4, sol.integerBreak(4));
   assertEquals(6, sol.integerBreak(5));
   assertEquals(9, sol.integerBreak(6));
   assertEquals(12, sol.integerBreak(7));
   assertEquals(18, sol.integerBreak(8));
   assertEquals(27, sol.integerBreak(9));
   assertEquals(36, sol.integerBreak(10));
 }