构造key为十六进制的字典。倒序遍历输入至第三位。 dic = {'0':0, '1':1, '2':2, '3':3, '4':4, '5':5, '6':6, '7':7, '8':8, '9':9, 'A':10, 'B':11, 'C':12, 'D':13, 'E':14, 'F':15} res, cnt = 0, 1 for ch in input()[:1:-1]: res += dic[ch]*cnt cnt *= 16 print(res)
