Codeforces 204A

我也搞不懂为什么我每次做这种明明很简单清晰的题目总是会想出那么操蛋的办法，诶。贴个正常的:

#include <cstdio>
typedef long long LL;
LL a[20];
LL count(LL num){
    int bit[20],cnt = 0;
    LL tmp = num;
    while(tmp > 0){
        bit[cnt++] = tmp % 10;
        tmp /= 10;
    }
    if(cnt == 1)    return num - 1;
    LL ans = 9;
    for(int i = 1;i < cnt - 1;i++){
        ans += 9 * a[i-1];
    }
    ans += (bit[cnt-1] - 1) * a[cnt-2];
    for(int i = cnt-2;i >= 1;i--){
        ans += bit[i] * a[i-1];
    }
    if(bit[cnt-1] < bit[0]) ans++;
    return ans;
}
int main(){
    a[0] = 1;
    for(int i = 1;i <= 18;i++)  a[i] = a[i-1] * 10;
    LL L,R;
    while(scanf("%I64d%I64d",&L,&R) != EOF){
        printf("%I64d
",count(R+1)-count(L));
    }
    return 0;
}