2012-03-25 11:47:28Morris
[UVA][Math] 11038 - How Many O's?
Problem E: How many 0's?
A Benedict monk No. 16 writes down the decimal representations of all
natural numbers between and including m and n, m
≤ n. How many 0's will he write down?
Input consists of a sequence of lines. Each line contains two unsigned 32-bit integers m and n, m ≤ n. The last line of input has the value of m negative and this line should not be processed.
For each line of input print one line of output with one integer number giving the number of 0's written down by the monk.
Sample input
10 11 100 200 0 500 1234567890 2345678901 0 4294967295 -1 -1
Output for sample input
1 22 92 987654304 3825876150
做法 by http://www.knightzone.org/wordpress/archives/780
Ex.32053
十位數會出現0的情況=320*10^2
百位數會出現0的情況=(32-1)*10^3+(53+1)
#include <stdio.h>
long long calcZeros(long long n) {
if(n < 0) return 0;
long long sum = 1;
long long n10 = 1, ntail = 0;
while(n) {
if(n%10 != 0) {
sum += n/10*n10;
} else {
sum += (n/10-1)*n10 + (ntail+1);
}
ntail += n%10*n10;
n /= 10, n10 *= 10;
}
return sum;
}
int main() {
long long m, n;
while(scanf("%lld %lld", &m, &n) == 2) {
if(m < 0 && n < 0)
break;
printf("%lld\n", calcZeros(n)-calcZeros(m-1));
}
return 0;
}