From 8c3f0649271a343ea103f829daf9a75c47db2825 Mon Sep 17 00:00:00 2001
From: ShuangmingMa <52561813+ShuangmingMa@users.noreply.github.com>
Date: Sat, 16 Sep 2023 20:35:17 +0800
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---
 problems/0042.接雨水.md | 39 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/problems/0042.接雨水.md b/problems/0042.接雨水.md
index 760ebc34..517ccb0b 100644
--- a/problems/0042.接雨水.md
+++ b/problems/0042.接雨水.md
@@ -704,6 +704,45 @@ func min(x, y int) int {
 }
 ```
 
+单调栈压缩版：
+
+```go
+func trap(height []int) int {
+    stack := make([]int, 0)
+    res := 0
+
+    // 无需事先将第一个柱子的坐标入栈，因为它会在该for循环的最后入栈
+    for i := 0; i < len(height); i ++ {
+        // 满足栈不为空并且当前柱子高度大于栈顶对应的柱子高度的情况时
+        for len(stack) > 0 && height[stack[len(stack) - 1]] < height[i] {
+            // 获得凹槽高度
+            mid := height[stack[len(stack) - 1]]
+            // 凹槽坐标出栈
+            stack = stack[: len(stack) - 1]
+
+            // 如果栈不为空则此时栈顶元素为左侧柱子坐标
+            if len(stack) > 0 {
+                // 求得雨水高度
+                h := min(height[i], height[stack[len(stack) - 1]]) - mid
+                // 求得雨水宽度
+                w := i - stack[len(stack) - 1] - 1
+                res += h * w
+            }
+        }
+        // 如果栈为空或者当前柱子高度小于等于栈顶对应的柱子高度时入栈
+        stack = append(stack, i)
+    }
+    return res
+}
+
+func min(x, y int) int {
+    if x < y {
+        return x
+    }
+    return y
+}
+```
+
 ### JavaScript:
 
 ```javascript