题解 | #[NOIP2010]数字统计#

#include <stdio.h>

int caculate(int a,int b){
    int m = 0, k = 0, count =0;
    for (; a <= b; a++) {
        k = a;
        while (k) {
            m = k%10;
            k/=10;
            if (m==2) {
                count++;
            }
        }
    }
    return count;
}
int main() {
    int a, b;
    while (scanf("%d %d", &a, &b) != EOF) { // 注意 while 处理多个 case
        // 64 位输出请用 printf("%lld") to 
        printf("%d\n", caculate(a, b));
    }
    return 0;
}