resolve 85

Author: lilyhe123

src/083.py

@@ -0,0 +1,34 @@
+"""
+question 83
+Invert a binary tree.
+
+For example, given the following tree:
+
+   a
+  / \
+ b   c
+/ \\ /
+d e  f
+
+should become:
+
+  a
+ /  \
+c    b
+\\  /  \
+ f  e   d
+
+-------------------
+
+For every node its left and right child needs to be swapped.
+This needs to be done to every node in the tree.
+We can do this in recursive way (DFS) or interative way (BFS)
+"""
+
+
+def invertTree():
+    pass
+
+
+def test_83():
+    pass

src/084.py

@@ -0,0 +1,27 @@
+"""
+question 84
+Given a matrix of 1s and 0s, return the number of "islands" in the matrix. A 1
+represents land and 0 represents water, so an island is a group of 1s that are
+neighboring whose perimeter is surrounded by water.
+
+For example, this matrix has 4 islands.
+
+1 0 0 0 0
+0 0 1 1 0
+0 1 1 0 0
+0 0 0 0 0
+1 1 0 0 1
+1 1 0 0 1
+
+-------------------
+
+
+"""
+
+
+def number_of_island():
+    pass
+
+
+def test_84():
+    pass

src/085.py

@@ -0,0 +1,20 @@
+"""
+question 85
+Given three 32-bit integers x, y, and b, return x if b is 1 and y if b is 0,
+using only mathematical or bit operations. You can assume b can only be 1 or 0.
+
+-------------------
+
+"""
+
+
+def x_or_y(x, y, b):
+    return x * b + y * (1 - b)
+
+
+def test_85():
+    assert x_or_y(10, 12, 1) == 10
+    assert x_or_y(10, 12, 0) == 12
+
+
+test_85()

src/ds/classes.py

@@ -101,7 +101,7 @@ def print(self):
 
 
 class TreeNode:
-    def __init__(self, val: int, left: object = None, right: object = None):
+    def __init__(self, val, left: object = None, right: object = None):
         self.val = val
         self.left = left
         self.right = right

src/utils/format.py renamed to src/utils/formatter.py

@@ -1,15 +1,18 @@
 #
 # Utility to generate code template for a question.
 #
-# Read problem description from a file.
+# Read from a file.
 # The first line of the file is the question number.
+# Remaining lines are the problem's description.
+
 # Generate an output file with the description included in a block comment.
 # with each line less than 80.
 # and create question function and test function.
 #
+import os
 
-from_file = "src/question.txt"
-to_file = "src/daily.py"
+from_file = "src/utils/question.txt"
+to_dir = "src/"
 
 
 def format_question(text: str, num: int, limit: int) -> str:
@@ -46,30 +49,26 @@ def read_and_format(input_file, output_file):
     with open(input_file, "r") as input_obj:
         lines = input_obj.readlines()
         text = ""
+        suffix = ""
         for i, line in enumerate(lines):
             if i == 0:
+                suffix = line.strip()
+                while len(suffix) < 3:
+                    suffix = "0" + suffix
                 num = int(line.strip())
             else:
                 text += line
-
+    output_file += suffix + ".py"
+    if os.path.isfile(output_file):
+        print(output_file, "already exists. Do nothing.")
+        return
     output = format_question(text, num, 80)
-    test_method = "test_" + str(num) + "()"
-    with open(output_file, "a+") as output_obj:
-        output_obj.seek(0)
-        lines = output_obj.readlines()
-        for line in lines:
-            if test_method in line:
-                print(
-                    "The question is already included in ",
-                    output_file + ".",
-                    "Do Nothing.",
-                )
-                return
+    with open(output_file, "w") as output_obj:
         output_obj.write(output)
 
 
 def generate():
-    read_and_format(from_file, to_file)
+    read_and_format(from_file, to_dir)
 
 
 if __name__ == "__main__":

src/utils/question.txt

@@ -1,4 +1,2 @@
-82
-Using a read7() method that returns 7 characters from a file, implement readN(n) which reads n characters.
-
-For example, given a file with the content “Hello world”, three read7() returns “Hello w”, “orld” and then “”.
+85
+Given three 32-bit integers x, y, and b, return x if b is 1 and y if b is 0, using only mathematical or bit operations. You can assume b can only be 1 or 0.