232 implement queue using stacks

Cargo.toml

@@ -6,4 +6,5 @@ members = [
     "three_sum",
     "binary_tree_postorder_traversal",
     "two_sum",
+    "implement_queue_using_stacks",
 ]

README.md

@@ -10,8 +10,9 @@ Resolving problems of LeetCode in RustLang.
 * [1. Two Sum](./two_sum/src/lib.rs)
 * [7. Reverse Integer](./reverse_integer/src/lib.rs)
 * [15. 3 Sum](./three_sum/src/lib.rs)
-* [215. Kth Largest Element in an Array](./kth_largest/src/lib.rs)
 * [145. Binary Tree Postorder Traversal](./binary_tree_postorder_traversal/src/lib.rs)
+* [215. Kth Largest Element in an Array](./kth_largest/src/lib.rs)
+* [232. Implement Queue using Stacks](./implement_queue_using_stacks/src/lib.rs)
 
 ## Document
 

implement_queue_using_stacks/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "implement_queue_using_stacks"
+version = "0.1.0"
+authors = ["Ryan Li <conbas2019@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

implement_queue_using_stacks/src/lib.rs

@@ -0,0 +1,54 @@
+/*!
+ * # 232. Implement Queue using Stacks
+ *
+ * * [Problem link](https://leetcode.com/problems/implement-queue-using-stacks/)
+ */
+
+#![allow(dead_code)]
+
+struct MyQueue {
+    start: usize,
+    data: Vec<i32>,
+}
+
+impl MyQueue {
+    fn new() -> Self {
+        MyQueue {
+            start: 0,
+            data: vec![],
+        }
+    }
+
+    fn push(&mut self, x: i32) {
+        self.data.push(x);
+    }
+
+    fn pop(&mut self) -> i32 {
+        let v = self.data[self.start];
+        self.start += 1;
+        v
+    }
+
+    fn peek(&self) -> i32 {
+        self.data[self.start]
+    }
+
+    fn empty(&self) -> bool {
+        self.start == self.data.len()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_example() {
+        let mut queue = MyQueue::new();
+        queue.push(1);
+        queue.push(2);
+        assert_eq!(queue.peek(), 1);
+        assert_eq!(queue.pop(), 1);
+        assert!(!queue.empty());
+    }
+}