interview problems: trees

src/extra_interview_problems/bitwise/get_bit.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+
+__author__ = "bt3"
+
+''' Get a bit in a binary number:
+    1) Shifts 1 over by i bits
+    2) make an AND with the number
+    3) all the other than the bit at i are clean, now compare to 0
+    4) if the new value is not 0, bit i is 1
+'''
+
+
+def get_bit(num, i):
+    mask = 1 << i
+    return num & mask != 0
+
+
+if __name__ == '__main__':
+    num = int('0100100', 2)
+    get_bit(num, 0)   # 0
+    get_bit(num, 1)   # 0
+    get_bit(num, 2)   # 1
+    get_bit(num, 3)   # 0
+    get_bit(num, 4)   # 0
+    get_bit(num, 5)   # 1
+    get_bit(num, 6)   # 0
+