completed warmup-2 problems

Author: saurabhmithe

Solutions/warmup-2/array123.py

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+# Given an array of ints, return True if the sequence of
+# numbers 1, 2, 3 appears in the array somewhere.
+
+# array123([1, 1, 2, 3, 1]) → True
+# array123([1, 1, 2, 4, 1]) → False
+# array123([1, 1, 2, 1, 2, 3]) → True
+
+
+def array123(nums):
+    for i in range(0, len(nums) - 2):
+        if nums[i] == 1 and nums[i+1] == 2 and nums[i+2] == 3:
+            return True
+    return False

Solutions/warmup-2/array_front9.py

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+# Given an array of ints, return True if one of the first 4 elements
+# in the array is a 9. The array length may be less than 4.
+
+# array_front9([1, 2, 9, 3, 4]) → True
+# array_front9([1, 2, 3, 4, 9]) → False
+# array_front9([1, 2, 3, 4, 5]) → False
+
+
+def array_front9(nums):
+    if len(nums) >= 4:
+        return 9 in nums[:4]
+    return 9 in nums

Solutions/warmup-2/string_match.py

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+# Given 2 strings, a and b, return the number of the positions
+# where they contain the same length 2 substring. So "xxcaazz"
+# and "xxbaaz" yields 3, since the "xx", "aa", and "az"
+# substrings appear in the same place in both strings.
+
+# string_match('xxcaazz', 'xxbaaz') → 3
+# string_match('abc', 'abc') → 2
+# string_match('abc', 'axc') → 0
+
+
+def string_match(a, b):
+    shorter = min(len(a), len(b))
+    count = 0
+    for i in range(shorter - 1):
+        if a[i] == b[i] and a[i+1] == b[i+1]:
+            count += 1
+    return count