From 25d018e5aaa3740901d987cbce0fa2cd4e61ece1 Mon Sep 17 00:00:00 2001
From: phoenix <phoenixzero4@gmail.com>
Date: Mon, 29 Jun 2026 12:56:15 -0400
Subject: [PATCH] TrappingRain and Streams

---
 .../TrappingRainWater.java                    | 49 +++++++++++++++++++
 src/practice/streams/Streams.java             | 46 +++++++++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 src/codecademy/javaInterviewProblems/TrappingRainWater.java
 create mode 100644 src/practice/streams/Streams.java

diff --git a/src/codecademy/javaInterviewProblems/TrappingRainWater.java b/src/codecademy/javaInterviewProblems/TrappingRainWater.java
new file mode 100644
index 0000000..17bdc9a
--- /dev/null
+++ b/src/codecademy/javaInterviewProblems/TrappingRainWater.java
@@ -0,0 +1,49 @@
+package codecademy.javaInterviewProblems;
+
+public class TrappingRainWater {
+
+    static int naiveSolution(int[] heights) {
+
+        int sum = 0;
+        int leftMax = 0, leftIndex = 0;
+        int rightMax = 0, rightIndex = heights.length - 1;
+
+        for (int i = 0; i < heights.length; i++) {
+            int leftBound = 0;
+            int rightBound = 0;
+
+            for (int j = 0; j <= i; j++) {
+                leftBound = Math.max(leftBound, heights[j]);
+            }
+
+            for (int j = i; j < heights.length; j++) {
+                rightBound = Math.max(rightBound, heights[j]);
+            }
+
+            sum += Math.min(leftBound, rightBound) - heights[i];
+        }
+
+        return sum;
+    }
+
+    static void main(String[] args) {
+        int[] heights = {7, 0, 9, 5, 9};
+        System.out.println(naiveSolution(heights));
+        System.out.println(optimizedSolution(heights));
+    }
+
+    public static int optimizedSolution(int[] heights) {
+        int totalWater = 0, leftMax = 0, rightMax = 0;
+        int leftIndex = 0, rightIndex = heights.length - 1;
+
+        while (leftIndex < rightIndex) {
+            leftMax = Math.max(leftMax, heights[leftIndex]);
+            rightMax = Math.max(rightMax, heights[rightIndex]);
+            totalWater += Math.min(leftMax, rightMax) - heights[leftIndex];
+            if (leftMax <= rightMax) leftIndex++;
+            else rightIndex--;
+        }
+
+        return totalWater;
+    }
+}
diff --git a/src/practice/streams/Streams.java b/src/practice/streams/Streams.java
new file mode 100644
index 0000000..2d08de4
--- /dev/null
+++ b/src/practice/streams/Streams.java
@@ -0,0 +1,46 @@
+package practice.streams;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class Streams {
+
+
+    static Employee[] employees = {
+            new Employee(1, "John", 10000),
+            new Employee(2, "Jane", 12000),
+            new Employee(3, "Bob", 15000)
+    };
+
+
+    static void main(String[] args) {
+
+        Stream.of(employees).forEach(e -> System.out.println(e.name));
+
+        Stream.of(employees).filter(e -> e.salary > 10000).forEach(e -> System.out.println(e.id + " " + e.name + " " + e.salary));
+
+        List<Employee> empList = Arrays.asList(employees);
+        System.out.println(empList.stream());
+
+        Stream.of(employees[0], employees[1], employees[2]);
+        Stream.Builder<Employee> builder = Stream.builder();
+        builder.accept(employees[0]);
+        builder.accept(employees[1]);
+        builder.accept(employees[2]);
+        builder.build().forEach(e -> System.out.println(e.id + " " + e.name + " " + e.salary));
+    }
+
+    static class Employee {
+        int id;
+        String name;
+        double salary;
+
+        public Employee(int id, String name, double salary) {
+            this.id = id;
+            this.name = name;
+            this.salary = salary;
+        }
+    }
+
+}