# include<stdio.h> # include<math.h> # include<stdbool.h> bool isPrime(int n){ bool flag=true; if(n==0||n==1){ flag=false; } for(int i=2;i<=sqrt(n);i++){ if(n%i==0){ flag=false; break; } } return flag; } int main(){ int h1,m1,h2,m2,t1,t2,count; int t,h,m; while(scanf("%d:%d %d:%d",&h1,&m1,&h2,&m2)!=EOF){ count=0; t1=h1*60+m1; t2=h2*60+m2; t=t1; h=h1; m=m1; while(t1<=t&&t<=t2){ if(isPrime(h*2500+m)){ count++; } t++; h=t/60; m=t%60; } printf("%d",count); } return 0; } |
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