leetcode 204. Count Primes
Count the number of prime numbers less than a non-negative number, n.Example:
Input: 10
Output: 4
Explanation: There are 4 prime numbers less than 10, they are 2, 3, 5, 7.
class Solution {
public int countPrimes(int n) {
if(n <= 1) return 0;
boolean[] arr = new boolean;
arr = true;
arr = true;
for(int i = 2; i < Math.sqrt(n) ; i++){
if(arr == false){
for(int j = 2 ; j*i < n; j++){
arr = true;
}
}
}
int count = 0;
for(int i = 2; i< arr.length; i++){
if(!arr) count++;
}
return count;
}
}
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