Create 042.Trapping-Rain-Water_stack.cpp

slowpeace2020 · May 24, 2020 · 52df7f4 · 52df7f4
1 parent 7eff1ea
commit 52df7f4
Showing 1 changed file with 23 additions and 0 deletions.
diff --git a/Others/042.Trapping-Rain-Water/042.Trapping-Rain-Water_stack.cpp b/Others/042.Trapping-Rain-Water/042.Trapping-Rain-Water_stack.cpp
@@ -0,0 +1,23 @@
+class Solution {
+public:
+    int trap(vector<int>& height) 
+    {
+        stack<int>Stack;
+        int ret = 0;
+
+        for (int i=0; i<height.size(); i++)
+        {
+            while (!Stack.empty() && height[Stack.top()] < height[i])
+            {                
+                int base = height[Stack.top()];
+                Stack.pop();
+                if (Stack.empty()) continue;
+                int h = min(height[Stack.top()], height[i]) - base;
+                int w = i - Stack.top()-1;
+                ret += h*w;                
+            }
+            Stack.push(i);
+        }
+        return ret;
+    }
+};