leetcode: Add 0155

src/leetcode/0155.min-stack/Cargo.toml

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+[package]
+name = "lc-0155-min-stack"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]

src/leetcode/0155.min-stack/index.md

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+
+# 
+
+[问题描述](../problems/)

src/leetcode/0155.min-stack/src/bin/double.rs

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+// Copyright (c) 2024 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by General Public License that can be found
+// in the LICENSE file.
+
+// 用两个栈来实现
+
+#[derive(Debug, Clone)]
+pub struct MinStack {
+    // 正常的栈, 按入栈顺序存储.
+    stack: Vec<i32>,
+    // 最小栈, 里面存储当前位置的最小元素, 最小元素可能是有重复的,
+    // 其长度与 `stack` 相同.
+    min_stack: Vec<i32>,
+}
+
+impl Default for MinStack {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl MinStack {
+    #[must_use]
+    #[inline]
+    pub const fn new() -> Self {
+        Self {
+            stack: Vec::new(),
+
+            min_stack: Vec::new(),
+        }
+    }
+
+    pub fn push(&mut self, val: i32) {
+        self.stack.push(val);
+        if let Some(top) = self.min_stack.last() {
+            self.min_stack.push(*top.min(&val));
+        } else {
+            self.min_stack.push(val);
+        }
+    }
+
+    pub fn pop(&mut self) {
+        let _ = self.stack.pop();
+        let _ = self.min_stack.pop();
+    }
+
+    #[must_use]
+    pub fn top(&self) -> i32 {
+        self.stack.last().copied().unwrap_or_default()
+    }
+
+    #[must_use]
+    pub fn get_min(&self) -> i32 {
+        self.min_stack.last().copied().unwrap_or_default()
+    }
+
+    #[must_use]
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.stack.is_empty()
+    }
+}
+
+fn check_solution() {
+    let mut obj = MinStack::new();
+    obj.push(-2);
+    obj.push(0);
+    obj.push(-3);
+    assert_eq!(obj.get_min(), -3);
+    obj.pop();
+    assert_eq!(obj.top(), 0);
+    assert_eq!(obj.get_min(), -2);
+}
+
+fn main() {
+    check_solution();
+}
+
+#[cfg(test)]
+mod tests {
+    use super::check_solution;
+
+    #[test]
+    fn test_min_stack() {
+        check_solution();
+    }
+}

src/leetcode/0155.min-stack/src/bin/single.rs

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+// Copyright (c) 2024 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by General Public License that can be found
+// in the LICENSE file.
+
+// 用一个栈来实现
+#[derive(Debug, Clone)]
+pub struct MinStack {
+    // 元组: (当前的元素, 当前最小的元素)
+    stack: Vec<(i32, i32)>,
+}
+
+impl Default for MinStack {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl MinStack {
+    #[must_use]
+    #[inline]
+    pub const fn new() -> Self {
+        Self { stack: Vec::new() }
+    }
+
+    pub fn push(&mut self, val: i32) {
+        if let Some(top) = self.stack.last() {
+            let min = top.1.min(val);
+            self.stack.push((val, min));
+        } else {
+            self.stack.push((val, val));
+        }
+    }
+
+    pub fn pop(&mut self) {
+        let _ = self.stack.pop().unwrap();
+    }
+
+    #[must_use]
+    pub fn top(&self) -> i32 {
+        self.stack.last().unwrap().0
+    }
+
+    #[must_use]
+    pub fn get_min(&self) -> i32 {
+        self.stack.last().unwrap().1
+    }
+
+    #[must_use]
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.stack.is_empty()
+    }
+}
+
+fn check_solution() {
+    let mut obj = MinStack::new();
+    obj.push(-2);
+    obj.push(0);
+    obj.push(-3);
+    assert_eq!(obj.get_min(), -3);
+    obj.pop();
+    assert_eq!(obj.top(), 0);
+    assert_eq!(obj.get_min(), -2);
+}
+
+fn main() {
+    check_solution();
+}
+
+#[cfg(test)]
+mod tests {
+    use super::check_solution;
+
+    #[test]
+    fn test_min_stack() {
+        check_solution();
+    }
+}