题解 | #数位五五#

#include <stdio.h>

int main() {
    int a, b, count = 0;
    scanf("%d %d", &a, &b);
    for (int i = a; i <= b; i++) {
        int n = i, sum = 0;
        while (n) {
            sum += n % 10;
            n /= 10;
        }
        if (sum % 5 == 0) {
            count++;
        }
    }
    printf("%d\n", count);
    return 0;
}