The above picture is from Sina Weibo, showing May 23rd, 2019 as a very cool “Prime Day”. That is, not only that the corresponding number of the date 20190523
is a prime, but all its sub-strings ended at the last digit 3
are prime numbers.
Now your job is to tell if a given date is a Prime Day.
Input Specification:
Each input file contains one test case. For each case, a date between January 1st, 0001 and December 31st, 9999 is given, in the format yyyymmdd
.
Output Specification:
For each given date, output in the decreasing order of the length of the substrings, each occupies a line. In each line, print the string first, followed by a space, then Yes
if it is a prime number, or No
if not. If this date is a Prime Day, print in the last line All Prime!
.
Sample Input 1:
20190523
Sample Output 1:
20190523 Yes
0190523 Yes
190523 Yes
90523 Yes
0523 Yes
523 Yes
23 Yes
3 Yes
All Prime!
Sample Input 2:
20191231
Sample Output 2:
20191231 Yes
0191231 Yes
191231 Yes
91231 No
1231 Yes
231 No
31 Yes
1 No
#include<iostream> #include<algorithm> #include<math.h> #include<string> using namespace std; bool is_prime(int n) { if (n == 1||n == 0) return false; for (int i = 2; i < sqrt(n); i++) { if (n % i == 0) return false; } return true; } int stringtoint(string str) { int ans=0; for (int i = 0; i < 8; i++) { ans += (str[i]-'0') * (int)pow(10, 8 - i - 1); } return ans; } int main() { string num; cin >> num; int num_i = stringtoint(num); //cout << num_i; bool is_all_prime = true; for (int i = 0; i < 8; i++) { int temp; bool isprime; temp = num_i % (int)(pow(10, 8 - i)); isprime = is_prime(temp); for (int j = i; j < 8; j++) { cout << num[j]; } cout << ' '; if (isprime == 1)cout << "Yes"; else { is_all_prime = false; cout << "No"; } if (i < 7)cout << endl; } if (is_all_prime == 1)cout <
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