2012 Multi-University Training Contest 8

 1 #include<iostream>
 2 #include<string.h>
 3 #include<stdio.h>
 4 #define INF 3000000000
 5 #define LL long long
 6 using namespace std;
 7 
 8 int main(){
 9     LL n,A,B,l,mod,num,a;
10     LL max1,min,M;
11     while(~scanf("%I64d%I64d%I64d%I64d%I64d",&n,&l,&A,&B,&mod)){
12         max1=-1,num=0;min=INF;M=l/2;
13         for(LL i=1;i<=n;i++){
14             if (i==1) a=(A+B)%mod;else a=(a+A)%mod;
15             if (a<=M){
16                 if (a>max1) max1=a;
17                 num++;
18             }
19             else{
20                if (a<min) min=a;
21             }
22         }
23         if (max1+min<=l) num++;
24         printf("%I64d\n",num);
25     }
26     return 0;
27 
28 }