init

problems/p35/src/main.rs

@@ -0,0 +1,43 @@
+use std::str::FromStr;
+
+use primal::is_prime;
+
+// 有0，2, 4, 5, 6, 8的，必然不是
+fn is_circular_prime(num: u32) -> bool {
+    if num == 2 || num == 3 || num == 5 || num == 7 {
+        return true;
+    }
+    let mut str_num = num.to_string();
+    if str_num.contains("0")
+        || str_num.contains("2")
+        || str_num.contains("4")
+        || str_num.contains("5")
+        || str_num.contains("6")
+        || str_num.contains("8")
+    {
+        return false;
+    }
+
+    for _ in 0..str_num.len() {
+        let num = u32::from_str(&str_num).unwrap();
+        if !is_prime(num as u64) {
+            return false;
+        }
+        str_num = str_num[1..str_num.len()].to_string() + &str_num[0..1];
+    }
+
+    true
+}
+#[test]
+fn test_is_circular_prime() {
+    assert!(is_circular_prime(2));
+    assert!(is_circular_prime(5));
+    assert!(is_circular_prime(13));
+    assert!(!is_circular_prime(4));
+    assert!(is_circular_prime(197));
+}
+
+fn main() {
+    let count = (0..1000000u32).filter(|x| is_circular_prime(*x)).count();
+    println!("{count}");
+}