add 1.7_rotate_matrix.py

Author: bap2pecs0

Cracking_the_coding_interview/v6/1.7_rotate_matrix.py

@@ -0,0 +1,66 @@
+'''Question:
+Given an image represented by an NxN matrix, where each pixel in the image is 
+4 bytes, write a method to rotate the image by 90 degrees. 
+
+Can you do this in place?
+
+clarifications:
+- assume rotate closewise
+- input: matrix
+- return: None
+'''
+
+from math import ceil
+import copy
+import unittest
+from test_utils import UnitTestBase
+
+# Solution:
+# Hint: draw a 4x4 matrix as an example
+# Time: O(N*N)
+# Space: O(1)
+# Hotspot: if N is odd, it will be wrong to use range(ceil(n/2)) to loop i.
+# The reason is it will end up rotating twice for some cells
+def rotate_matrix(matrix):
+  n = len(matrix)
+  for i in range(n//2):
+    for j in range(ceil(n/2)):
+      tmp = matrix[i][j]
+      matrix[i][j] = matrix[n - 1 - j][i]
+      matrix[n - 1 - j][i] = matrix[n - 1 - i][n - 1 - j]
+      matrix[n - 1 - i][n - 1 - j] = matrix[j][n - 1 - i]
+      matrix[j][n - 1 - i] = tmp
+
+class TestStrComp(UnitTestBase, unittest.TestCase):
+  def data_provider(self):
+    return [
+      ([], []),
+      ([['1111']], [['1111']]),
+      ([['1111','2222'], ['3333','4444']], [['3333','1111'], ['4444','2222']]),
+      ([['1111','2222','3333'], ['4444','5555','6666'], ['7777','8888','9999']],
+       [['7777','4444','1111'], ['8888','5555','2222'], ['9999','6666','3333']],
+      ),
+      ([['1111','2222','3333', '4444'], 
+        ['5555','6666','7777', '8888'], 
+        ['9999','0000','aaaa', 'bbbb'],
+        ['cccc','dddd','eeee', 'ffff']],
+       [['cccc','9999','5555', '1111'], 
+        ['dddd','0000','6666', '2222'], 
+        ['eeee','aaaa','7777', '3333'],
+        ['ffff','bbbb','8888', '4444']],
+      ),
+    ]
+
+  def func_provider(self):
+    return [
+      rotate_matrix,
+    ]
+
+  def single_test(self, func, data):
+    cpy = copy.deepcopy(data)
+    matrix = data[0]
+    func(matrix)
+    self.expect(matrix, func, cpy)
+
+if __name__ == '__main__':
+  unittest.main()

Cracking_the_coding_interview/v6/__pycache__/test_utils.cpython-36.pyc

@@ -1,4 +1,5 @@
 from abc import ABC, abstractmethod
+import copy
 
 class UnitTestBase(ABC):
 
@@ -10,15 +11,18 @@ def data_provider(self):
   def func_provider(self):
     pass
 
-  @abstractmethod
   def func_eval(self, func, args):
     pass
 
   def test(self):
     for func in self.func_provider():
       for data in self.data_provider():
-        args = data[0]
-        self.expect(self.func_eval(func, args), func, data)
+        self.single_test(func, data)
+
+  def single_test(self, func, data):
+    args = data[0]
+    cpy = copy.deepcopy(data)
+    self.expect(self.func_eval(func, args), func, cpy)
 
   def expect(self, result, func, data):
     expected = data[1]

Cracking_the_coding_interview/v6/test_utils.py

@@ -35,7 +35,7 @@
 5) bitwise operators: x<<y, x>>y, x&y, x|y, ~x, x^y
 6) for i in range(len(lst)-1,-1,-1):
 7) {char:[] for char in Set}
-8) min(lst, key=foo)
+8) min(lst, key=foo); min(string_1, string2, len)
 9) min(result_l,result_r,key=lambda x:x[0])
 10) lst = [[k,v] for k,v in dic.items()]
 11) lst = filter(lambda item: item != '', lst)