Sync LeetCode submission Runtime - 11 ms (45.67%), Memory - 6.3 MB (1…

…6.84%)

leetcode/0042-trapping-rain-water/solution.go

@@ -0,0 +1,18 @@
+func trap(height []int) int {
+    n := len(height)
+    left := make([]int, n)
+    right := make([]int, n)
+    left[0] = height[0]
+    right[n-1] = height[n-1]
+    for i := 1;i<n;i++ {
+        left[i] = max(left[i-1], height[i])
+    }
+    for i := n-2;i>=0;i-- {
+        right[i] = max(right[i+1], height[i])
+    }
+    ret := 0
+    for i := 0;i<n;i++ {
+        ret += min(left[i], right[i]) - height[i]
+    }
+    return ret
+}