func isPrime(n int) bool {
for i := 2; i*i <= n; i++ {
if n%i == 0 {
return false
}
}
return n >= 2 // 1 不是质数
}
func diagonalPrime(nums [][]int) (ans int) {
for i, row := range nums {
if x := row[i]; x > ans && isPrime(x) {
ans = x
}
if x := row[len(nums)-1-i]; x > ans && isPrime(x) {
ans = x
}
}
return
}
class Solution {
public int diagonalPrime(int[][] nums) {
int n = nums.length, ans = 0;
for (int i = 0; i < n; ++i) {
int x = nums[i][i];
if (x > ans && isPrime(x))
ans = x;
x = nums[i][n - 1 - i];
if (x > ans && isPrime(x))
ans = x;
}
return ans;
}
private boolean isPrime(int n) {
for (int i = 2; i * i <= n; ++i)
if (n % i == 0)
return false;
return n >= 2; // 1 不是质数
}
}
def is_prime(n: int) -> bool:
i = 2
while i * i <= n:
if n % i == 0:
return False
i += 1
return n >= 2 # 1 不是质数
class Solution:
def diagonalPrime(self, nums: List[List[int]]) -> int:
ans = 0
for i, row in enumerate(nums):
for x in row[i], row[-1 - i]:
if x > ans and is_prime(x):
ans = x
return ans
