L1-028. Judge prime number, l1-028 judge Prime Number

L1-028. Judge prime number, l1-028 judge Prime Number

The objective of this question is to determine whether a given positive integer is a prime number.

Input Format:

The input returns a positive integer N (<= 10) in the first row, followed by N rows. Each row returns a positive integer smaller than 231.

Output Format:

For each positive integer to be judged, if it is a prime number, "Yes" is output in a row; otherwise, "No" is output ".

Input example:

211111

Output example:

YesNo

Time Limit: 400 ms memory limit: 65536 kB code length limit: 8000 B Judgment program Standard author Chen Yue Note: (1) the number of questions required to be input is a positive integer, so we need to consider the case of 1, 1 is not a prime number; (2) when determining whether a number is a prime number, you only need to traverse from 2 to the square root of the number. If there is a fully divided number, you can exit the loop. This reduces the time complexity.

#include <stdio.h>#include <stdlib.h>#include <math.h>int main(){    int n;    int i, j;    int arr[10];    int flog = 0;    scanf("%d", &n);    if(n > 10 || n < 0)        exit(0);    for(i = 0; i < n; i++)    {        scanf("%d", &arr[i]);    }    for(i = 0; i < n; i++)    {        if(arr[i] == 1)            printf("No\n");        else{        flog = 0;        for(j = 2; j <= sqrt(arr[i]); j++)        {            if(arr[i]%j == 0)            {                flog = 1;                break;            }        }        if(flog == 1)            printf("No\n");        else            printf("Yes\n");        }    }    return 0;}