organization in the src structure, modification of README

src/EXTRA_INTERVIEW_PROBLEMS/bitwise/bitwise.txt

@@ -0,0 +1,33 @@
+				BIT-WISE
+			----------------------
+
+1. To find a number:
+11000101 is 2^0+2^2+2^6+2^7 = 197
+
+
+2. Left shifting:
+	0010 1011 << 4  ---> 1011 000
+
+
+3. Right shifting:
+	0010 1011 >> 4	---> 0000 0010
+	or it can be filled with the copy of the first bit, instead of 0:
+	1011 0010 >> 4  ---> 1111 1011
+
+
+4. XOR can cancels out:
+15 ^ 12 ^ 15 = 12
+
+
+5. 2^x:
+	left-shift 1 by x:
+	0000 0001 << x
+
+	so if x = 2, 2^2 = 4 -> 100
+
+	0000 0001 << 2  ---> 0000 0100
+
+
+6. Is power of 2?
+	just do x&(x-1).
+	if 0 --> yes!