233. Number of Digit One【H】【33】【再来一遍】

Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.

For example:
Given n = 13,
Return 6, because digit 1 occurred in the following numbers: 1, 10, 11, 12, 13.

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按位算，先算个位数的1 有多少个，再算十位数的，依次往上

写了好多遍啊。。。。

class Solution(object):    def countDigitOne(self, n):        if n < 1:            return 0        b = 0        t = 1        res = 0        while t <= n:            b = n / (t*10)            tres = b * t            temp = (n / t)%10            if temp == 10:                temp = 1            if temp == 1:                tres += n % t + 1            elif temp > 1:                tres += t            res += tres            #print t,b,tres            t *= 10        return  int(res)