C++

LeetCode/Trapping-Rain-Water/C++.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+
+class Solution {
+public:
+    int trap(vector<int>& height) {
+        int l = 0, r = height.size() - 1, water = 0, minHeight = 0;
+        while (l < r) {
+            while (l < r && height[l] <= minHeight) {
+                water += minHeight - height[l++];
+            }
+            while (l < r && height[r] <= minHeight) {
+                water += minHeight - height[r--];
+            }
+            minHeight = min(height[l], height[r]);
+        }
+        return water;
+    }
+};

LeetCode/Trapping-Rain-Water/ReadmeForcpp.md

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+Intuition for my code:
+
+Set two pointers l and r to the left and right end of height. 
+Then we get the minimum height (minHeight) of these pointers since the level of the water cannot be higher than it.
+Then we move the two pointers towards the center.
+If the coming level is less than minHeight, then it will hold some water.
+Fill the water until we meet some "barrier" (with height larger than minHeight) and update l and r to repeat this process