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アルファベットを1〜26の数字に変換して名前リストの総和を求めるメソッドをテスト駆動開発する（Project Euler 問22）

今回の問題 Names scores Using names.txt (right click and ‘Save Link/Target As…’), a 46K text file […]

今回の問題 Amicable numbers Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divid […]

今回の問題 Factorial digit sum n! means n × (n − 1) × … × 3 × 2 × 1 For example, 10! = 10 × 9 × … × 3 × […]

今回の問題 Counting Sundays You are given the following information, but you may prefer to do some research for you […]

今回の問題 Maximum path sum I By starting at the top of the triangle below and moving to adjacent numbers on the ro […]

今回の問題 Number letter counts If the numbers 1 to 5 are written out in words: one, two, three, four, five, then t […]

今回の問題 Power digit sum 2**15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26. What is the sum of th […]

今回の問題 Lattice paths Starting in the top left corner of a 2×2 grid, and only being able to move to the right an […]

今回の問題 Longest Collatz sequence The following iterative sequence is defined for the set of positive integers: n […]

今回の問題 Large sum Work out the first ten digits of the sum of the following one-hundred 50-digit numbers. 以下の50桁 […]