finish extra/fuel-injection-perfection

README.md

@@ -74,3 +74,5 @@ CFcSBwgCCBoHRhkKU1cGAA4AGU5YQR5THBwNFwoGGAxTQQMQVBUSBg4EAAwQRhUQVBUHFAQTGRpT QQM
 ### find-the-access-codes
 * Completed in: 1 hr, 6 mins, 52 secs.
 
+### fuel-injection-perfection
+* Completed in: 1 hr, 2 secs.

extra/fuel-injection-perfection/constraints.txt

@@ -0,0 +1,21 @@
+Java
+====
+Your code will be compiled using standard Java 8. All tests will be run by calling the solution() method inside the Solution class
+
+Execution time is limited.
+
+Wildcard imports and some specific classes are restricted (e.g. java.lang.ClassLoader). You will receive an error when you verify your solution if you have used a blacklisted class.
+
+Third-party libraries, input/output operations, spawning threads or processes and changes to the execution environment are not allowed.
+
+Your solution must be under 32000 characters in length including new lines and and other non-printing characters.
+
+Python
+======
+Your code will run inside a Python 2.7.13 sandbox. All tests will be run by calling the solution() function.
+
+Standard libraries are supported except for bz2, crypt, fcntl, mmap, pwd, pyexpat, select, signal, termios, thread, time, unicodedata, zipimport, zlib.
+
+Input/output operations are not allowed.
+
+Your solution must be under 32000 characters in length including new lines and and other non-printing characters.

extra/fuel-injection-perfection/readme.txt

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+Fuel Injection Perfection
+=========================
+
+Commander Lambda has asked for your help to refine the automatic quantum antimatter fuel injection system for the LAMBCHOP doomsday device. It's a great chance for you to get a closer look at the LAMBCHOP -- and maybe sneak in a bit of sabotage while you're at it -- so you took the job gladly. 
+
+Quantum antimatter fuel comes in small pellets, which is convenient since the many moving parts of the LAMBCHOP each need to be fed fuel one pellet at a time. However, minions dump pellets in bulk into the fuel intake. You need to figure out the most efficient way to sort and shift the pellets down to a single pellet at a time. 
+
+The fuel control mechanisms have three operations: 
+
+1) Add one fuel pellet
+2) Remove one fuel pellet
+3) Divide the entire group of fuel pellets by 2 (due to the destructive energy released when a quantum antimatter pellet is cut in half, the safety controls will only allow this to happen if there is an even number of pellets)
+
+Write a function called solution(n) which takes a positive integer as a string and returns the minimum number of operations needed to transform the number of pellets to 1. The fuel intake control panel can only display a number up to 309 digits long, so there won't ever be more pellets than you can express in that many digits.
+
+For example:
+solution(4) returns 2: 4 -> 2 -> 1
+solution(15) returns 5: 15 -> 16 -> 8 -> 4 -> 2 -> 1
+Quantum antimatter fuel comes in small pellets, which is convenient since the many moving parts of the LAMBCHOP each need to be fed fuel one pellet at a time. However, minions dump pellets in bulk into the fuel intake. You need to figure out the most efficient way to sort and shift the pellets down to a single pellet at a time. 
+
+The fuel control mechanisms have three operations: 
+
+1) Add one fuel pellet
+2) Remove one fuel pellet
+3) Divide the entire group of fuel pellets by 2 (due to the destructive energy released when a quantum antimatter pellet is cut in half, the safety controls will only allow this to happen if there is an even number of pellets)
+
+Write a function called solution(n) which takes a positive integer as a string and returns the minimum number of operations needed to transform the number of pellets to 1. The fuel intake control panel can only display a number up to 309 digits long, so there won't ever be more pellets than you can express in that many digits.
+
+For example:
+solution(4) returns 2: 4 -> 2 -> 1
+solution(15) returns 5: 15 -> 16 -> 8 -> 4 -> 2 -> 1
+
+Languages
+=========
+
+To provide a Python solution, edit solution.py
+To provide a Java solution, edit Solution.java
+
+Test cases
+==========
+Your code should pass the following test cases.
+Note that it may also be run against hidden test cases not shown here.
+
+-- Python cases --
+Input:
+solution.solution('15')
+Output:
+    5
+
+Input:
+solution.solution('4')
+Output:
+    2
+
+-- Java cases --
+Input:
+Solution.solution('4')
+Output:
+    2
+
+Input:
+Solution.solution('15')
+Output:
+    5
+
+Use verify [file] to test your solution and see how it does. When you are finished editing your code, use submit [file] to submit your answer. If your solution passes the test cases, it will be removed from your home folder.

extra/fuel-injection-perfection/solution.py

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+def solution(n):
+    # 1.  *0: /= 2
+    # 2. *01: -= 1
+    # 3. *11: += 1
+
+    # state 0: *0
+    # state 1: *1
+    # state 2: *11
+    result = 0
+    state = 0
+    count = 0
+    b = bin(int(n))[2:]
+    for c in bin(int(n))[:1:-1]:
+        if c == '0':
+            if state == 0: # 0*
+                count += 1
+            elif state == 1: # 01
+                result += 1 + 2 # remove one, divide by 2 twice
+                count = 0
+                state = 0 # .*01 => .*00 => .*
+            elif state == 2: # 01*
+                result += 1 + count # add one, divide by 2 count times
+                count = 1
+                state = 1 # .*01* => .*10* => .*1
+        if c == '1':
+            if state == 0: # 10*
+                result += count # divide by 2 count times
+                count = 1
+                state = 1 # .*10* => .*1
+            elif state == 1: # 11
+                count += 1
+                state = 2
+            elif state == 2: # 1*
+                count += 1
+    if state == 2: # 11*
+        if count == 2: # 11
+            result += 2
+        else:
+            result += 1 + count # add one, devide by 2 count times
+    return result
+
+
+tests = [
+        ('15', 5),
+        ('4', 2),
+        (str(int('1', 2)), 0),
+        (str(int('10', 2)), 1),
+        (str(int('11', 2)), 2),
+        (str(int('100', 2)), 2),
+        (str(int('101', 2)), 3),
+        (str(int('110', 2)), 3),
+        (str(int('111', 2)), 4),
+        (str(int('1000', 2)), 3),
+        (str(int('1001', 2)), 4),
+        (str(int('1010', 2)), 4),
+        (str(int('1011', 2)), 6),
+        (str(int('1100', 2)), 4),
+        (str(int('1101', 2)), 5),
+        (str(int('1110', 2)), 5),
+        (str(int('1111', 2)), 5),
+        (str(int('10001', 2)), 5),
+        (str(int('111110', 2)), 7),
+        (str(int('101111', 2)), 7),
+        (str(int('1101111', 2)), 9),
+        (str(int('10001000', 2)), 8),
+        (str(int('11001100', 2)), 10),
+        (str(int('10101010', 2)), 10),
+        (str(int('11011000', 2)), 10),
+        (str(int('10000000', 2)), 7),
+        ]
+
+for i, o in tests:
+    result = solution(i)
+    print (i, result == o, result, o)