leetcode: Add cpp impl to 0155

src/SUMMARY.md

@@ -272,6 +272,7 @@
         - [0137. 只出现一次的数字II Single Number II](leetcode/0137.single-number-ii/index.md)
         - [0153. 寻找旋转排序数组中的最小值 Find Minimum in Rotated Sorted Array](leetcode/0153.find-minimum-in-rotated-sorted-array/index.md)
         - [0154. 寻找旋转排序数组中的最小值 II Find Minimum in Rotated Sorted Array II](leetcode/0154.find-minimum-in-rotated-sorted-array-ii/index.md)
+        - [0155. 最小栈 Min Stack](leetcode/0155.min-stack/index.md)
         - [0162. 寻找峰值 Find Peak Element](leetcode/0162.find-peak-element/index.md)
         - [0167. 两数之和 II - 输入有序数组 Two Sum II - Input Array Is Sorted](leetcode/0167.two-sum-ii-input-array-is-sorted/index.md)
         - [0189. 旋转数组 Rotate Array](leetcode/0189.rotate-array/index.md)

src/leetcode/0155.min-stack/.gitignore

@@ -0,0 +1,2 @@
+/dual-stack
+/single-stack

src/leetcode/0155.min-stack/Makefile

@@ -0,0 +1,6 @@
+
+dual-stack: dual-stack.cpp
+	g++ -g dual-stack.cpp -o dual-stack
+
+single-stack: single-stack.cpp
+	g++ -g single-stack.cpp -o single-stack

src/leetcode/0155.min-stack/dual-stack.cpp

@@ -0,0 +1,44 @@
+// 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.
+
+#include <cassert>
+
+#include <stack>
+
+class MinStack {
+ public:
+  MinStack() {}
+
+  void push(int val) {
+    this->stack_.push(val);
+    if (this->min_stack_.empty()) {
+      this->min_stack_.push(val);
+    } else {
+      const int current_min = this->min_stack_.top();
+      const int new_min = std::min(current_min, val);
+      this->min_stack_.push(new_min);
+    }
+  }
+
+  void pop() {
+    this->stack_.pop();
+    this->min_stack_.pop();
+  }
+
+  int top() {
+    return this->stack_.top();
+  }
+
+  int getMin() {
+    return this->min_stack_.top();
+  }
+
+ private:
+  std::stack<int> stack_;
+  std::stack<int> min_stack_;
+};
+
+int main() {
+  return 0;
+}

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

@@ -1,4 +1,36 @@
+# 0155. 最小栈 Min Stack
 
-# 
+[问题描述](https://leetcode.com/problems/min-stack)
 
-[问题描述](../problems/)
+这个问题可以有两种解法:
+
+- 使用两个栈, 分别存放正常的数值, 和当前位置的最小值
+- 使用一个栈, 但是栈中每个元素是一个元组, 分别存储 当前值和最小值
+
+## 使用两个栈
+
+### Rust
+
+```rust
+{{#include src/bin/min-stack-with-dual-vec.rs:5:63}}
+```
+
+### C++
+
+```cpp
+{{#include dual-stack.cpp:5:40}}
+```
+
+## 使用一个栈
+
+### Rust
+
+```rust
+{{#include src/bin/min-stack-with-single-vec.rs:5:53}}
+```
+
+### C++
+
+```cpp
+{{#include single-stack.cpp:5:}}
+```

src/leetcode/0155.min-stack/single-stack.cpp

@@ -0,0 +1,42 @@
+// 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.
+
+#include <cassert>
+
+#include <stack>
+
+class MinStack {
+ public:
+  MinStack() {}
+
+  void push(int val) {
+    if (this->stack_.empty()) {
+      this->stack_.emplace(val, val);
+    } else {
+      const int current_min = this->getMin();
+      const int new_min = std::min(current_min, val);
+      this->stack_.emplace(val, new_min);
+    }
+  }
+
+  void pop() {
+    this->stack_.pop();
+  }
+
+  int top() {
+    return this->stack_.top().first;
+  }
+
+  int getMin() {
+    return this->stack_.top().second;
+  }
+
+ private:
+  std::stack<std::pair<int, int>> stack_;
+};
+
+int main() {
+  return 0;
+}
+

src/leetcode/0155.min-stack/src/bin/min-stack-with-dual-vec.rs

@@ -3,7 +3,6 @@
 // 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.
@@ -31,8 +30,10 @@ impl MinStack {
     }
 
     pub fn push(&mut self, val: i32) {
+        // 将元素入栈
         self.stack.push(val);
         if let Some(top) = self.min_stack.last() {
+            // 保存当前位置最小的元素到 min_stack.
             self.min_stack.push(*top.min(&val));
         } else {
             self.min_stack.push(val);

src/leetcode/tags/stack/index.md

@@ -6,7 +6,6 @@
 
 TODO:
 
-- [155.最小栈](https://leetcode.com/problems/min-stack)
 - [225.用队列实现栈](https://leetcode.com/problems/implement-stack-using-queues)
 - [682.棒球比赛](https://leetcode.com/problems/baseball-game)
 - [844.比较含退格的字符串](https://leetcode.com/problems/backspace-string-compare)
@@ -15,8 +14,9 @@ TODO:
 
 ## 中等
 
-1. [0071.简化路径 Simplify Path](../../0071.simplify-path/index.md)
-2. [0394. 字符串解码 Decode String](../../0394.decode-string/index.md)
+1. [0071. 简化路径 Simplify Path](../../0071.simplify-path/index.md)
+2. [0155. 最小栈 Min Stack](../../0155.min-stack/index.md)
+3. [0394. 字符串解码 Decode String](../../0394.decode-string/index.md)
 
 TODO: