diff --git a/src/main.rs b/src/main.rs
index 14dda91..9ff8cbd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,30 +1,38 @@
 mod arr;
-
 struct Solution {}
+use std::collections::HashSet;
 
 impl Solution {
-    pub fn get_common(nums1: Vec<i32>, nums2: Vec<i32>) -> i32 {
-        let (mut a, mut b) = (0,0);
-        loop {
-            if nums1[a] == nums2[b] {
-                return nums1[a];
-            }
-            if nums1[a] < nums2[b] {
-                a += 1;
-                if a >= nums1.len() {
-                    break;
-                }
-            } else {
-                b += 1;
-                if b >= nums2.len() {
-                    break;
-                }
+    pub fn longest_common_prefix(arr1: Vec<i32>, arr2: Vec<i32>) -> i32 {
+        let mut map = HashSet::new();
+        for &x in &arr1 {
+            let mut x = x;
+            while x > 0 {
+                map.insert(x);
+                x /= 10;
             }
         }
-        -1
+        let get_length = |x : i32| -> i32 {
+            x.to_string().len() as i32
+        };
+        let mut max_length = 0;
+        for &x in &arr2 {
+            let mut x = x;
+            while x > 0 {
+                if map.contains(&x) {
+                    max_length = max_length.max(get_length(x));
+                    break;
+                }
+                x /= 10;
+            }
+        }
+        max_length
     }
 }
 
 fn main() {
-    println!("{:?}", Solution::get_common(vec![1,2,3,6], vec![2,3,4,5]));
+    println!(
+        "{:?}",
+        Solution::longest_common_prefix(vec![1, 10, 100], vec![1000])
+    );
 }