题解 | 记数问题

#include <stdio.h>

int main() {
    int n = 0;
    int x = 0;
    int count = 0;
    scanf("%d %d", &n, &x);
    int arr[1000000] = { 0 };
    int i = 0;
    for (i = 0; i < n; i++) {
        arr[i] = i + 1;
    }
    for (i = 0; i < n; i++) {
        if (arr[i] > 9) {
            while (arr[i]) {
                if (arr[i] % 10 == x) {
                    count++;
                }
                arr[i] /= 10;
            }
        } else {
            if (arr[i] == x) {
                count++;
            }
        }
    }
    printf("%d\n", count);
    return 0;
}