From e066fd1c005e9a481b8d3913e09b9f3da216920c Mon Sep 17 00:00:00 2001
From: Xu Shaohua <shaohua@biofan.org>
Date: Wed, 8 May 2024 08:31:28 +0800
Subject: [PATCH] leetcode: Add 0155

---
 src/leetcode/0155.min-stack/Cargo.toml        |  7 ++
 src/leetcode/0155.min-stack/index.md          |  4 +
 src/leetcode/0155.min-stack/src/bin/double.rs | 87 +++++++++++++++++++
 src/leetcode/0155.min-stack/src/bin/single.rs | 78 +++++++++++++++++
 4 files changed, 176 insertions(+)
 create mode 100644 src/leetcode/0155.min-stack/Cargo.toml
 create mode 100644 src/leetcode/0155.min-stack/index.md
 create mode 100644 src/leetcode/0155.min-stack/src/bin/double.rs
 create mode 100644 src/leetcode/0155.min-stack/src/bin/single.rs

diff --git a/src/leetcode/0155.min-stack/Cargo.toml b/src/leetcode/0155.min-stack/Cargo.toml
new file mode 100644
index 00000000..300a5b69
--- /dev/null
+++ b/src/leetcode/0155.min-stack/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "lc-0155-min-stack"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
diff --git a/src/leetcode/0155.min-stack/index.md b/src/leetcode/0155.min-stack/index.md
new file mode 100644
index 00000000..77a618ba
--- /dev/null
+++ b/src/leetcode/0155.min-stack/index.md
@@ -0,0 +1,4 @@
+
+# 
+
+[问题描述](../problems/)
diff --git a/src/leetcode/0155.min-stack/src/bin/double.rs b/src/leetcode/0155.min-stack/src/bin/double.rs
new file mode 100644
index 00000000..aeeb71f9
--- /dev/null
+++ b/src/leetcode/0155.min-stack/src/bin/double.rs
@@ -0,0 +1,87 @@
+// Copyright (c) 2024 Xu Shaohua <shaohua@biofan.org>. 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();
+    }
+}
diff --git a/src/leetcode/0155.min-stack/src/bin/single.rs b/src/leetcode/0155.min-stack/src/bin/single.rs
new file mode 100644
index 00000000..6a0c9e81
--- /dev/null
+++ b/src/leetcode/0155.min-stack/src/bin/single.rs
@@ -0,0 +1,78 @@
+// Copyright (c) 2024 Xu Shaohua <shaohua@biofan.org>. 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();
+    }
+}