4029: [HEOI2015]定价 贪心

这个真是怎么贪心都能过了（然而我太弱了还是挂了好几遍）

#include<bits/stdc++.h>using namespace std;int L,R,T,mn,ans;inline int read(){    int a=0,f=1; char c=getchar();    while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}    while (c>='0'&&c<='9') {a=a*10+c-'0'; c=getchar();}    return a*f;}int add(int x){    int k=1;    while (x%10==0) k*=10,x/=10;    return k;}int calc(int x){    while (x%10==0) x/=10;    int t=x%10,a=0;    while (x) x/=10,a++;    if (t==5) return 2*a-1; return 2*a;}int main(){    T=read();    while (T--)    {        L=read(),R=read();        mn=calc(L); ans=L;        while (1)        {            L+=add(L);            if (L>R) break;            int t=calc(L);            if (t<mn) mn=t,ans=L;        }        printf("%d\n",ans);    }    return 0;}