diff --git a/Solutions/42TrappingRainWater.cpp b/Solutions/42TrappingRainWater.cpp
new file mode 100644
index 0000000..7dc41d5
--- /dev/null
+++ b/Solutions/42TrappingRainWater.cpp
@@ -0,0 +1,36 @@
+class Solution {
+public:
+    int trap(vector<int>& height) {
+        int n = height.size();
+        int lmax = height[0];
+        int rmax = height[n-1];
+        int lpos = 1;
+        int rpos = n-2;
+        int water = 0;
+        while(lpos <= rpos)
+        {
+            if(height[lpos] >= lmax)
+            {
+                lmax = height[lpos];
+                lpos++;
+            }
+            else if(height[rpos] >= rmax)
+            {
+                rmax = height[rpos];
+                rpos--;
+            }
+            else if(lmax <= rmax && height[lpos] < lmax)
+            {
+                water += lmax - height[lpos];
+                lpos++;
+            }
+            else
+            {
+                water += rmax - height[rpos];
+                rpos--;
+            }
+        
+        }
+        return water;
+    }
+};