From d77a99bf75ca7033ae3d5357408b566a2c1f1c9b Mon Sep 17 00:00:00 2001
From: nn <z15986352698@qq.com>
Date: Thu, 18 Sep 2025 21:15:28 +0800
Subject: [PATCH] =?UTF-8?q?20250918=E7=AC=AC=E4=B8=80=E5=91=A8=E7=BB=83?=
 =?UTF-8?q?=E4=B9=A0=E9=A2=98=E6=8E=A5=E9=9B=A8=E6=B0=B4?=
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---
 ..._\351\203\221\344\275\263\345\250\234.cpp" | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 "topic01/submit/LC0042_\351\203\221\344\275\263\345\250\234.cpp"

diff --git "a/topic01/submit/LC0042_\351\203\221\344\275\263\345\250\234.cpp" "b/topic01/submit/LC0042_\351\203\221\344\275\263\345\250\234.cpp"
new file mode 100644
index 0000000..a072f48
--- /dev/null
+++ "b/topic01/submit/LC0042_\351\203\221\344\275\263\345\250\234.cpp"
@@ -0,0 +1,35 @@
+#include <vector>
+#include <stack>
+using namespace std;
+
+class Solution {
+public:
+    int trap(vector<int>& height) {
+        if (height.empty()) return 0;
+        
+        stack<int> st;  // 单调栈，存储柱子的索引，保持栈内元素对应高度递减
+        int water = 0;  // 接雨水总量
+        
+        for (int i = 0; i < height.size(); ++i) {
+            // 当栈不为空且当前柱子高度大于栈顶柱子高度时，可能形成积水
+            while (!st.empty() && height[i] > height[st.top()]) {
+                int bottom = st.top();  // 凹槽底部的索引
+                st.pop();
+                
+                if (st.empty()) break;  // 没有左边界，无法形成积水
+                
+                int left = st.top();  // 左边界索引
+                int width = i - left - 1;  // 凹槽宽度
+                // 积水高度 = 左右边界的最小高度 - 凹槽底部高度
+                int height_diff = min(height[left], height[i]) - height[bottom];
+                
+                water += width * height_diff;  // 累加积水面积
+            }
+            st.push(i);  // 当前柱子索引入栈
+        }
+        
+        return water;
+    }
+};
+
+
-- 
Gitee