Python 代码

import sys

f = [[0] * 10 for _ in range(11)]

for i in range(10): 
    if i != 4: f[1][i] = 1
for i in range(2, 11):
    for j in range(10):
        if j == 4: continue 
        for k in range(10):
            if j == 6 and k == 2: continue
            if k == 4: continue
            f[i][j] += f[i-1][k]

def dp(x):
    if x == 0: return 1
    nums = []
    while x:
        nums.append(x % 10)
        x //= 10
    res = 0
    last = -1
    for i in range(len(nums)-1, -1, -1):
        num = nums[i]
        for j in range(num):
            if last == 6 and j == 2: continue
            elif j == 4: continue
            res += f[i+1][j]
        if last == 6 and num == 2: break
        if num == 4: break
        if i == 0: res += 1
        last = num
    return res

while True:
    line = sys.stdin.readline()
    L, R = map(int, line.split())
    if L == 0 and R == 0: break
    print(dp(R) - dp(L-1))