我怎样才能找到QT。号包括一个1在段[1..N]？ 例如：当n = 29是12;当n = 100是20。 n可以达到10 ^ 9，期限为2秒。 语言C ++

How can i find qt. numbers includes a 1 in the segment [1..n]? eg: for n=29 it is 12; for n=100 it is 20. n can reach 10^9 and time limit is 2 sec. language C++

推荐答案

一个简单的方法来检查，如果单号是计算其模10：如果是1，那么它，另有10并重复划分它。如果该数字是0，它不包括1

A simple way to check if a single number is to compute its modulo 10: if it's 1 then it does, otherwise divide it by 10 and repeat. If the number is 0, it doesn't include 1.

这应该足以让你开始。