题解 | #整数中1出现的次数）#
整数中1出现的次数（从1到n整数中1出现的次数）
https://www.nowcoder.com/practice/bd7f978302044eee894445e244c7eee6
不用数位dp，纯计算的最简代码
public class Solution {
public int NumberOf1Between1AndN_Solution(int n) {
int ret = 0;
for (long m = 1; m <= n; m *= 10) {
long a = n / m, b = n % m;
ret += (a + 8) / 10 * m + (a % 10 == 1 ? b + 1: 0);
}
return ret;
}
}
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