Add Python solution to challenge 137

2 files changed, 105 insertions, 0 deletions

diff --git a/challenge-137/paulo-custodio/python/ch-1.py b/challenge-137/paulo-custodio/python/ch-1.py
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+#!/usr/bin/env python3
+
+# TASK #1 > Long Year
+# Submitted by: Mohammad S Anwar
+# Write a script to find all the years between 1900 and 2100 which is a Long
+# Year.
+#
+# A year is Long if it has 53 weeks.
+#
+#
+# [UPDATED][2021-11-01 16:20:00]: For more information about Long Year, please
+# refer to wikipedia.
+#
+# Expected Output
+# 1903, 1908, 1914, 1920, 1925,
+# 1931, 1936, 1942, 1948, 1953,
+# 1959, 1964, 1970, 1976, 1981,
+# 1987, 1992, 1998, 2004, 2009,
+# 2015, 2020, 2026, 2032, 2037,
+# 2043, 2048, 2054, 2060, 2065,
+# 2071, 2076, 2082, 2088, 2093,
+# 2099
+
+# https://en.wikipedia.org/wiki/ISO_week_date#Weeks_per_year
+# years in which 1 January or 31 December are Thursdays
+
+import datetime
+
+def is_long_year(year):
+    dt = datetime.date(year, 1, 1)
+    if dt.isoweekday()==4:
+        return True
+    dt = datetime.date(year, 12, 31)
+    if dt.isoweekday()==4:
+        return True
+    return False
+
+years = list(filter(lambda x:is_long_year(x), range(1900, 2100+1)))
+for i in range(0, len(years), 5):
+    out = ", ".join([str(x) for x in years[i:i+5]])
+    if i+5 < len(years):
+        out += ","
+    print(out)
diff --git a/challenge-137/paulo-custodio/python/ch-2.py b/challenge-137/paulo-custodio/python/ch-2.py
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+#!/usr/bin/env python3
+
+# TASK #2 > Lychrel Number
+# Submitted by: Mohammad S Anwar
+# You are given a number, 10 <= $n <= 1000.
+#
+# Write a script to find out if the given number is Lychrel number. To keep the
+# task simple, we impose the following rules:
+#
+# a. Stop if the number of iterations reached 500.
+# b. Stop if you end up with number >= 10_000_000.
+#
+# [UPDATED][2021-11-01 16:20:00]: If you stop because of any of the above two
+# rules then we expect 1 as an output.
+#
+# According to wikipedia:
+#
+# A Lychrel number is a natural number that cannot form a palindrome through
+# the iterative process of repeatedly reversing its digits and adding the
+# resulting numbers.
+#
+# Example 1
+# Input: $n = 56
+# Output: 0
+#
+# After 1 iteration, we found palindrome number.
+# 56 + 65 = 121
+# Example 2
+# Input: $n = 57
+# Output: 0
+#
+# After 2 iterations, we found palindrome number.
+#  57 +  75 = 132
+# 132 + 231 = 363
+# Example 3
+# Input: $n = 59
+# Output: 0
+#
+# After 3 iterations, we found palindrome number.
+#  59 +  95 =  154
+# 154 + 451 =  605
+# 605 + 506 = 1111
+
+import sys
+
+MAX_ITER = 500
+MAX_NUM  = 10000000
+
+def is_lychrel(n):
+    for i in range(0, MAX_ITER):
+        if n > MAX_NUM:
+            break
+        rev_n = int(str(n)[::-1])
+        if n == rev_n:
+            return False
+        n += rev_n
+    return True
+
+if is_lychrel(int(sys.argv[1])):
+    print(1)
+else:
+    print(0)