feat: add gcj 2017 r0 init solutions and io template

Jessica Yung · Jessica Yung · commit afe3ebad23a9 · 2017-05-16T20:36:24.000+01:00
diff --git a/google-code-jam-2017/io_template.py b/google-code-jam-2017/io_template.py
@@ -0,0 +1,6 @@
+# input() reads a string with a line of input, stripping the '\n' (newline) at the end.
+# This is all you need for most Google Code Jam problems.
+t = int(input())  # read a line with a single integer
+for i in range(1, t + 1):
+  n, m = [int(s) for s in input().split(" ")]  # read a list of integers, 2 in this case
+  print("Case #{}: {} {}".format(i, n + m, n * m))
diff --git a/google-code-jam-2017/r0/1-oversized-pancake-flipper.py b/google-code-jam-2017/r0/1-oversized-pancake-flipper.py
@@ -0,0 +1,160 @@
+
+def k_to_flipper_int(k):
+    flipper_int = 0
+    for i in range(k):
+        flipper_int += 2**i
+    # print ("K = ", k, ", flipper_int = ", flipper_int)
+    return flipper_int
+
+
+def string_to_pancakes_int(string, to_int=True):
+    binary_string = ""
+    for char in string:
+        if char == "+":
+            binary_string += "0"
+        elif char == "-":
+            binary_string += "1"
+        else:
+            return "Error"
+    # print("String: ", string)
+    if to_int == True:
+        num = binary_string_to_int(binary_string)
+        # print("Pancake Int: ", num)
+        return num
+    else:
+        # print("Binary string: ", binary_string)
+        return binary_string
+
+def binary_string_to_int(string):
+    # print("Binary string: ", string)
+    binary_string_length = len(string)
+    num = 0
+    for i in range(1, binary_string_length+1):
+        digit = string[-i]
+        if digit == "1":
+           num += 2**(i-1)
+        elif string[-i] == "0":
+           pass
+        else:
+            return "Error"
+    # print("Pancake Sequence Int: ", num)
+    return num
+
+def largest_power_of_two_smaller_than(n):
+    # TODO:
+    # print("Largest power of two smaller than ", n, ":")
+    power = -1
+    while n > 0:
+        n = divmod(n, 2)[0]
+        power += 1
+    if power < 0:
+        return "Error: n <= 0"
+    power_of_two = 2**power
+    # print(power_of_two)
+    return power_of_two
+
+
+def pancake_flipper(pancakes_string, k):
+    flipper_int = k_to_flipper_int(k)
+    number_of_flips = 0
+    pancakes_int = string_to_pancakes_int(pancakes_string)
+    if pancakes_int % flipper_int == 0:
+        # It is possible
+        while pancakes_int != 0:
+            pancakes_int -= largest_power_of_two_smaller_than(pancakes_int)
+            number_of_flips += 1
+        # print ("Number of flips: ", number_of_flips)
+        return number_of_flips
+    else:
+        # print("Impossible")
+        return "Impossible"
+
+# k_to_flipper_int(5)
+# k_to_flipper_int(10)
+
+def v2_pancake_flipper(pancakes_string, k):
+    """O(n2) greedy algorithm.
+    Happy side up = 0, empty side up = 1."""
+    binary_list = list(string_to_pancakes_int(pancakes_string, to_int=False))
+    flips = 0
+    # for each distinct possible flip
+    for i in range(len(binary_list) - (k-1)):
+        # set active as leftmost pancake in flip
+        active = binary_list[i]
+        # if active is empty side up, flip
+        if active == '1':
+            # flip this pancake
+            binary_list[i] = '0'
+            # Flip the next (k-1) pancakes
+            for j in range(1,k):
+                binary_list[i+j] = str(abs(int(binary_list[i+j]) - 1))
+            # print updated pancake list
+            # print(binary_list)
+            flips += 1
+    # After all necessary flips completed
+    # if there are still empty side up pancakes, print 'IMPOSSIBLE'
+    for i in range(1, k):
+        # print("binary_list[-", i, "]: ", binary_list[-i])
+        if binary_list[-i] == "1":
+            # print("IMPOSSIBLE")
+            return "IMPOSSIBLE"
+    # print("Flips: ", flips)
+    return flips
+
+def v3_pancake_flipper(pancakes_string, k):
+    """O(n) greedy algorithm with memo-isation."""
+    binary_list = list(string_to_pancakes_int(pancakes_string, to_int=False))
+    flips = 0
+    flip_count = 0
+    n = len(pancakes_string)
+    unflip_at = [0] * n
+    # for each leftmost pancake
+    for i in range(n):
+        active = binary_list[i]
+        if unflip_at[i] == 1:
+            flip_count -= 1
+        # if active is empty side up
+        if (active == '1' and flip_count % 2 == 0) \
+                or (active == '0' and flip_count % 2 == 1):
+            # if there is still room to flip, flip
+            if i < (n - (k-1)):
+                print("Flip ", i)
+                # flip this pancake
+                flips += 1
+                flip_count += 1
+                if (i + k) <= n - 1:
+                    unflip_at[i + k] += 1
+            # if we can't flip, return 'IMPOSSIBLE'
+            else:
+                print(flip_count, active)
+                print("IMPOSSIBLE: -", i)
+                return "IMPOSSIBLE"
+    # print("Flips: ", flips)
+    return flips
+
+# Test cases:
+print(v3_pancake_flipper("---+-++-", 3))
+print(v2_pancake_flipper("---+-++-", 3))
+print(pancake_flipper("---+-++-", 3))
+"""
+import time
+
+start = time.time()
+long_string = "++--++--+++++++--+-+++----+++++++-+---+--+-++--+-" * 19
+v2_pancake_flipper(long_string, 8)
+end = time.time()
+print("Time taken: ", end - start "seconds")
+"""
+
+""" For Code Jam
+# input() reads a string with a line of input, stripping the '\n' (newline) at the end.
+# This is all you need for most Google Code Jam problems.
+t = int(input())  # read a line with a single integer
+for i in range(1, t + 1):
+  pancake_string, k = [s for s in input().split(" ")]  # read a list of integers, 2 in this case
+  # print("n, k: ", n, k)
+  k = int(k)
+  flips = v2_pancake_flipper(pancake_string, k)
+  print("Case #{}: {}".format(i, flips))
+  # check out .format's specification for more formatting options
+"""
diff --git a/google-code-jam-2017/r0/2-tidy-numbers.py b/google-code-jam-2017/r0/2-tidy-numbers.py
@@ -0,0 +1,42 @@
+def largest_tidy_number_smaller_than(n):
+    # print("n: ", n)
+    string_n = list(str(n))
+    length_of_n = len(string_n)
+    checked_all = False
+    changes = 0
+    while checked_all == False:
+        edited = False
+        for index in range(length_of_n-1):
+            if edited == False:
+                if string_n[index] > string_n[index + 1]:
+                    string_n[index] = str(int(string_n[index]) - 1)
+                        string_n[remaining_digit] = "9"
+                    """
+                    if string_n[index] >= string_n[index - 1]:
+                        # check applicable
+                    """
+                    edited = True
+                    changes += 1
+                    # print("New number: ", string_n)
+        if edited == False:
+            checked_all = True
+    # print("Changes:", changes)
+    string_n = ''.join(string_n)
+    n = int(string_n)
+    # print("Final number: ", n)
+    return n
+
+""" Test cases
+largest_tidy_number_smaller_than(132)
+largest_tidy_number_smaller_than(1000)
+largest_tidy_number_smaller_than(7)
+largest_tidy_number_smaller_than(11110)
+"""
+
+t = int(input())  # read a line with a single integer
+for i in range(1, t + 1):
+  n = input()
+  answer = largest_tidy_number_smaller_than(n)
+  # n, m = [int(s) for s in input().split(" ")]  # read a list of integers, 2 in this case
+  print("Case #{}: {}".format(i, answer))
+  # check out .format's specification for more formatting options
diff --git a/google-code-jam-2017/r0/3-bathroom-stalls.py b/google-code-jam-2017/r0/3-bathroom-stalls.py
@@ -0,0 +1,58 @@
+def split(n):
+    if n % 2 == 0:
+        return [n/2, n/2 - 1]
+    elif n % 2 == 1:
+        width = n // 2
+        return [width, width]
+    else:
+        return "Error"
+
+def bathroom_stalls(n, k):
+    intervals = [n]
+    max_min_pair = []
+    for i in range(k):
+        intervals = sorted(intervals, reverse=True)
+        active = intervals[0]
+        print("Max: ", active)
+        max_min_pair = split(active)
+        # TODO: replace active with max_min_pair
+        intervals = intervals[1:] + max_min_pair
+        print("max_min: ", max_min_pair)
+    max_min_pair = [int(j) for j in max_min_pair]
+    return max_min_pair
+
+def bathroom_stalls_v2(n, k):
+    intervals = [0]*n + [1]
+    max_min_pair = []
+    active = n
+    active_qty = 1
+    for i in range(k):
+        # 1) while last element is zero, eliminate
+        # print("intervals: ", intervals)
+        while active_qty == 0:
+            # add one or something
+            active -= 1
+        intervals = intervals[:active+1]
+        # print("Max: ", active)
+        max_min_pair = split(active)
+        # TODO: replace active with max_min_pair
+        max = int(max_min_pair[0])
+        min = int(max_min_pair[1])
+        # Update intervals
+        intervals[max] += 1
+        intervals[min] += 1
+        intervals[active] -= 1
+        # print("max_min: ", max_min_pair)
+        active_qty -= 1
+    max_min_pair = [int(j) for j in max_min_pair]
+    return max_min_pair
+
+# input() reads a string with a line of input, stripping the '\n' (newline) at the end.
+# This is all you need for most Google Code Jam problems.
+t = int(input())  # read a line with a single integer
+for i in range(1, t + 1):
+  n, k = [int(s) for s in input().split(" ")]  # read a list of integers, 2 in this case
+  # print("n, k: ", n, k)
+  max_min_pair = bathroom_stalls_v2(n, k)
+  print("Case #{}: {} {}".format(i, max_min_pair[0], max_min_pair[1]))
+  # check out .format's specification for more formatting options
