为何洛谷AC，普及80？？

#include<cstdio>
#include<iostream>
#include<algorithm>
int a,b,i,j,k,l,y1,y2,m1,m2,d1,d2,s,sum;
int t[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int fz(int x)
{
    int k=0,ans=0;
    while(x>0){
        k=x%10;
        ans=ans*10+k;
        x/=10;
    }    
    return ans;
}
int pd(int x){
    if((x%4==0 && x%100!=0)||x%400==0)return 1;
    return 0;
}
using namespace std;
int main()
{
    scanf("%d%d",&a,&b);
    printf("%d\n%d\n",fz(a),fz(b));
   while(a<=b){
    y1=a/10000;
    m1=a/100%100;
    d1=a%100;
    if(a==fz(a))sum++;
    if(pd(y1)==1)t[3]=29;
    else t[3]=28;
    if(d1<t[m1])
    a++;
    else if(d1==t[m1]&&m1<12)
        a=a-t[m1]+1+100;
    else if(d1==t[m1]&&m1==12)
        a=a-t[m1]+1-1200+100+10000;
    }
    printf("%d",sum);
    return 0;
}