20240304 Finished

src/problem/mod.rs

@@ -63,3 +63,4 @@ mod p2581_count_number_of_possible_root_nodes;
 mod p2369_check_if_there_is_a_valid_partition_for_the_array;
 mod p2368_reachable_nodes_with_restrictions;
 mod p225_implement_stack_using_queues;
+mod p232_implement_queue_using_stacks;

src/problem/p232_implement_queue_using_stacks.rs

@@ -0,0 +1,84 @@
+/**
+ * [232] Implement Queue using Stacks
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+use std::collections::VecDeque;
+
+struct MyQueue {
+    in_stack: VecDeque<i32>,
+    out_stack: VecDeque<i32>
+}
+
+
+/**
+ * `&self` means the method takes an immutable reference.
+ * If you need a mutable reference, change it to `&mut self` instead.
+ */
+impl MyQueue {
+
+    fn new() -> Self {
+        MyQueue {
+            in_stack: VecDeque::new(),
+            out_stack: VecDeque::new()
+        }
+    }
+    
+    fn push(&mut self, x: i32) {
+        self.in_stack.push_back(x);
+    }
+    
+    fn pop(&mut self) -> i32 {
+        if self.out_stack.is_empty() {
+            while let Some(top) = self.in_stack.pop_back() {
+                self.out_stack.push_back(top);
+            }
+        }
+
+        self.out_stack.pop_back().unwrap()
+    }
+    
+    fn peek(&mut self) -> i32 {
+        if self.out_stack.is_empty() {
+            while let Some(top) = self.in_stack.pop_back() {
+                self.out_stack.push_back(top);
+            }
+        }
+
+        *self.out_stack.back().unwrap()
+    }
+    
+    fn empty(&self) -> bool {
+        self.out_stack.is_empty() && self.in_stack.is_empty()
+    }
+}
+
+/**
+ * Your MyQueue object will be instantiated and called as such:
+ * let obj = MyQueue::new();
+ * obj.push(x);
+ * let ret_2: i32 = obj.pop();
+ * let ret_3: i32 = obj.peek();
+ * let ret_4: bool = obj.empty();
+ */
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_232() {
+        let mut queue = MyQueue::new();
+
+        queue.push(1);
+        queue.push(2);
+
+        assert_eq!(1, queue.peek());
+        assert_eq!(1, queue.pop());
+        assert!(!queue.empty());
+    }
+}