1049 Counting Ones (30 分)
The task is simple: given any positive integer N, you are supposed to count the total number of 1‘s in the decimal form of the integers from 1 to N. For example, given N being 12, there are five 1‘s in 1, 10, 11, and 12.
Input Specification:
Each input file contains one test case which gives the positive N (≤2?30??).
Output Specification:
For each test case, print the number of 1‘s in one line.
Sample Input:
12
Sample Output:
5
题目大意:给出一个数m,计算1~m中的数包含的所有的1的个数。
//我绝对是看过这道题,但是真的想不起来怎么做了,当时就没怎么看懂。数据量这么大,指定不能一个一个算,需要技巧。
//个位是1+十位是1+。。。。。这样会不会有重复?不会吧。
//这个真的好难,看了好久才明白。
如何计算left和now和right也值得注意!自己求的话就不太会求的。
原文地址:https://www.cnblogs.com/BlueBlueSea/p/9862926.html
时间: 2024-10-03 10:30:30