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Day25_LeetCode42.java

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+class Solution {
+    public int trap(int[] height) {
+        int n = height.length ;
+        int[] leftMax = new int[n];
+        leftMax[0]=height[0];
+
+        for(int i=1;i<n;i++){
+            leftMax[i] = Math.max(leftMax[i-1],height[i]);
+        }
+
+        int[] rightMax = new int[n];
+        rightMax[n-1]=height[n-1];
+        for(int i=n-2;i>=0;i--){
+            rightMax[i] = Math.max(rightMax[i+1],height[i]);
+        }
+
+        int ans = 0 ;
+        for(int i=0;i<n;i++){
+            ans += Math.min(leftMax[i],rightMax[i])-height[i];
+        }
+
+        return ans ;
+    }
+}

Day25_LeetCode42.md

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+**Day 25: LeetCode 42 [Trapping Rain water]**
+
+**Problem Description:**
+
+
+**Link to LeetCode Problem:**
+https://leetcode.com/problems/trapping-rain-water/description/