diff --git a/src/bin/lc-373.rs b/src/bin/lc-373.rs
new file mode 100644
index 0000000..c76032d
--- /dev/null
+++ b/src/bin/lc-373.rs
@@ -0,0 +1,34 @@
+use std::cmp::Ordering;
+
+struct Solution;
+
+impl Solution {
+    pub fn k_smallest_pairs(nums1: Vec<i32>, nums2: Vec<i32>, k: i32) -> Vec<Vec<i32>> {
+        use std::collections::{BinaryHeap,HashSet};
+        let mut pq = BinaryHeap::<(i32,usize,usize)>::new();
+        pq.push((-nums1[0]-nums2[0],0,0));
+        let m=nums1.len();
+        let n = nums2.len();
+        let mut vis = HashSet::<(usize,usize)>::new();
+        let mut res = Vec::new();
+        let mut cnt = 0;
+        while let Some((_,i,j)) = pq.pop() {
+            if vis.contains(&(i,j)) {continue;}
+            vis.insert((i,j));
+            res.push(vec![nums1[i],nums2[j]]);
+            cnt += 1;
+            if cnt == k as usize {break;}
+            if i+1!=m {
+                pq.push((-nums1[i+1]-nums2[j],i+1,j));
+            }
+            if j+1!=n {
+                pq.push((-nums1[i]-nums2[j+1],i,j+1));
+            }
+        }
+        res
+    }
+}
+
+fn main() {
+
+}
\ No newline at end of file
diff --git a/src/bin/lc-402.rs b/src/bin/lc-402.rs
new file mode 100644
index 0000000..f5b971a
--- /dev/null
+++ b/src/bin/lc-402.rs
@@ -0,0 +1,34 @@
+use std::collections::VecDeque;
+
+struct Solution;
+
+impl Solution {
+    pub fn remove_kdigits(num: String, k: i32) -> String {
+        use std::collections::VecDeque;;
+        let num = num.into_bytes();  // TODO
+        let mut st = VecDeque::<u8>::new();
+        let mut cnt = 0;
+        for x in num {
+            while let Some(&y) = st.back() {
+                if x >= y || cnt == k { break; }
+                st.pop_back();
+                cnt += 1;
+            }
+            st.push_back(x);
+        }
+        for _ in cnt..k {
+            st.pop_back();
+        }
+        while let Some(48) = st.front() {
+            st.pop_front();
+        }
+        if st.is_empty() { st.push_back(48); }
+        String::from_utf8(st.into_iter().collect::<Vec<u8>>()).unwrap()
+    }
+}
+
+fn main() {
+    let num = "1432219".to_string();
+    let k = 3;
+    println!("{}",Solution::remove_kdigits(num,k));
+}
\ No newline at end of file
diff --git a/src/bin/lc-406.rs b/src/bin/lc-406.rs
new file mode 100644
index 0000000..78e52ef
--- /dev/null
+++ b/src/bin/lc-406.rs
@@ -0,0 +1,23 @@
+struct Solution;
+
+impl Solution {
+    pub fn reconstruct_queue(mut people: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
+        people.sort_unstable_by(|x,y|{
+            if x[0] == y[0] {
+                x[1].cmp(&y[1])
+            } else {
+                y[0].cmp(&x[0])
+            }
+        });
+        let n = people.len();
+        let mut res = Vec::<Vec<i32>>::with_capacity(n);
+        for curr in people {
+            res.insert(curr[1] as usize, curr);
+        }
+        res
+    }
+}
+
+fn main() {
+
+}
\ No newline at end of file
diff --git a/src/bin/lc-409.rs b/src/bin/lc-409.rs
new file mode 100644
index 0000000..ef0f2f5
--- /dev/null
+++ b/src/bin/lc-409.rs
@@ -0,0 +1,27 @@
+struct Solution;
+
+impl Solution {
+    pub fn longest_palindrome(s: String) -> i32 {
+        use std::collections::HashMap;
+        let mut s = s.into_bytes();
+        let mut mp = HashMap::<u8,i32>::new();
+        for i in s {
+            if let Some(&v) = mp.get(&i) {
+                mp.insert(i,v+1);
+            }else{
+                mp.insert(i,1);
+            }
+        }
+        let mut res = 0;
+        let mut f = 0;
+        for (_,v) in mp {
+            if v & 1 != 0 { f = 1; }
+            res += v >> 1;
+        }
+        res + f
+    }
+}
+
+fn main() {
+
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 41cd7a3..ad8afc4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,15 +1,10 @@
-trait Printable<T> {
-    fn print(a:T);
-}
-
-struct Test;
-
-impl<T> Printable<T> for Test where T: std::fmt::Display {
-    fn print(a:T) {
-        println!("{a}");
-    }
-}
-
+mod test_mod;
+mod test_mods;
+mod a_sibling_file;
 fn main() {
-    <Test>::print(1.5);
-}
+    use test_mod::a_mod::hello_world;
+    use test_mods::another_mod;
+    hello_world();
+    another_mod::another_fn();
+    a_sibling_file::sibling_mod::sibling_fn();
+}
\ No newline at end of file