complete 2022.rs 1264.rs 1318.rs 3731.rs 4633.rs 7140.rs 7541.rs 14315.rs 17204.rs 25208.rs

storage/zeta/rs/completed/17204.rs

@@ -0,0 +1,45 @@
+use std::io::{read_to_string, stdin};
+
+fn main() {
+    let temp = read_to_string(stdin()).unwrap();
+    let mut iter = temp
+        .split_ascii_whitespace()
+        .map(|x| x.parse::<usize>().unwrap());
+    let (n, k) = (iter.next().unwrap(), iter.next().unwrap());
+
+    let mut edges = vec![0; n];
+    let mut flg = false;
+    (0..n).for_each(|i| {
+        let nxt = iter.next().unwrap();
+        edges[i] = nxt;
+        if nxt == k {
+            flg = true;
+        }
+    });
+
+    if !flg {
+        println!("{}", -1);
+        return;
+    }
+
+    let mut curr = 0;
+    let mut nxt;
+    let mut vis = vec![false; n];
+    let mut m = 0;
+    'a: loop {
+        if vis[curr] {
+            m = -1;
+            break;
+        } else {
+            vis[curr] = true;
+        }
+        if curr == k {
+            break 'a;
+        }
+        nxt = edges[curr];
+
+        curr = nxt;
+        m += 1;
+    }
+    println!("{}", m);
+}