Codeforce205C Little Elephant and Interval

题意：输入l, r输出所有[l, r]内的首位和个位相同的数字的个数

题解：数位dp可以写，有一种更简单的方法，只要把前l-1位看作一个整体，可以取[1, x/10)任意数,个位补充就可以

#include <bits/stdc++.h>
#define maxn 101000
#define INF 0x3f3f3f3f
typedef long long ll;
using namespace std;
ll num;
ll solve(ll x){
    if(x<10) return x;
    ll t = x;
    while(x){
        num = x%10;
        x /= 10;
    }
    return 8+t/10+(t%10>=num?1:0);
}
int main(){
    ll l, r;
    //cout<<solve(47)<<endl;
    cin>>l>>r;
    cout<<solve(r)-solve(l-1)<<endl;
    return 0;
}