P1217求助

P1217 [USACO1.5] 回文质数 Prime Palindromes

本人小白一个,实在不知道怎么做了
by liaoyancheng @ 2024-03-06 21:47:19


把cout改成printf试试,应该会快一点
by a_sir @ 2024-03-06 21:51:02


@[a_sir](/user/1125673) 我都换了,但为什么之前对的都错了,之前超时的还是超时 ``` #include<bits/stdc++.h> using namespace std; bool f=1; void zs(long long n) { if(n%3==0||n%5==0||n%7==0||n%11==0||n%13==0) { if(n>13) { f=0; } else { long long i; if(n%2==0) { f=0; } for(i=3;i<n;i+=2) { if(n%i==0) { f=0; } if(f==0) { break; } } } } else { long long i; if(n%2==0) { f=0; } for(i=13;i<n;i+=2) { if(n%i==0) { f=0; } if(f==0) { break; } } } } void hws(long long n) { long long a=n,b=0,s=0; while(a>0) { b=b*10+a%10; a/=10; s++; if(b==0) { f=0; break; } } if(b!=n) { f=0; } if(s%2==0) { if(n!=11) { f=0; } } } int main () { long long c,a,b; scanf("%I64d %I64d",&a,&b); if(a%2==0) c=a+1; else c=a; for(long long i=c;i<=b;i+=2) { if(i>=9989899) { printf("9989899"); break; } else { hws(i); if(f==1) { zs(i); if(f==1) { printf("%I64d \n",i); } } f=1; } } return 0; } ``` 能帮我看一下怎么回事吗
by liaoyancheng @ 2024-03-06 22:05:11


呵呵,我也不会,我不是大佬
by ZHE333 @ 2024-03-18 13:43:18


@[liaoyancheng](/user/1219677) 此题无需开long long int即可
by V_HAPPY666 @ 2024-04-20 07:24:59


@[V_HAPPY666](/user/1247040) 我主要问题就是要超时
by liaoyancheng @ 2024-04-20 11:52:43


@[liaoyancheng](/user/1219677) 循环变量太大了,我建议你定义全局变量
by V_HAPPY666 @ 2024-04-20 18:48:10


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