- 問題
Problem 42：Coded triangle numbers
The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1); so the first ten triangle numbers are:1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
By converting each letter in a word to a number corresponding to its alphabetical position and adding these values we form a word value. For example, the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a triangle number then we shall call the word a triangle word.
Using words.txt (right click and 'Save Link/Target As...'), a 16K text file containing nearly two-thousand common English words, how many are triangle words?
- 解答例
def listTriNum(num): list = [1] i = 2 while i * (i + 1) // 2 <= num: list.append(i * (i + 1) // 2) i += 1 return list num = { "A":1, "B":2, "C":3, "D":4, "E":5, "F":6, "G":7, "H":8, "I":9, "J":10, "K":11, "L":12, "M":13, "N":14, "O":15, "P":16, "Q":17, "R":18, "S":19, "T":20, "U":21, "V":22, "W":23, "X":24, "Y":25, "Z":26} f = open("p042_words.txt", "r") name = [] for line in f: text = line.replace('\n', '') text = text.replace('\r', '') text = text.replace('"', '') name = text.split(",") f.close() maxLen = 0 for n in name: if maxLen < len(n): maxLen = len(n) triangleNum = listTriNum(maxLen * 26) count = 0 for n in name: score = 0 temp = list(n) for x in temp: score += num[x] if score in triangleNum: count += 1 print(n, score) print(count)
- 用意したファイル（p042_words.txt）
