How to evaluate Reverse Polish Notation?

Introduction🛹

Hey guys, Today is day 15 of the 100 Days to** LinkedIn Challenge.**

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If you are Preparing for your Interview. Even if you are settled down in your job, keeping yourself up-to-date with the latest **Interview Problems **is essential for your career growth. Start your **prep **from Here!

Last month, I have been researching to find out the Frequently asked problems from these Companies. I have compiled **100 **of these questions, I am not promising you that you will get these questions in your interview but I am confident that most of these “interview questions” have similar logic and employs the same way of thinking from these set of challenges.

Before we move on to the first problem, If you are wondering why I chose LinkedIn, Yahoo and Oracle over FAANG is because I have completed a challenge Focusing on Amazon and Facebook Interview Questions in this Series:

New Day, New Strength, New Thoughts🚀

Day 15 — Reverse Polish Notation🏁

AIM🏹

Evaluate the value of an arithmetic expression in Reverse Polish Notation.

Valid operators are +-*/. Each operand may be an integer or another expression.

Note:

  • Division between two integers should truncate toward zero.
  • The given RPN expression is always valid. That means the expression would always evaluate to a result and there won’t be any divide by zero operation.

Example🕶

Input: ["2", "1", "+", "3", "*"]
Output: 9
Explanation: ((2 + 1) * 3) = 9

Input: ["4", "13", "5", "/", "+"]
Output: 6
Explanation: (4 + (13 / 5)) = 6

Code👇

	class Solution {
	    public int evalRPN(String[] tokens) {
	        Stack<Integer> stack = new Stack<Integer>();
	        for(String element : tokens)
	        {
	            if(!"+-*/".contains(element))
	            {
	                stack.push(Integer.valueOf(element));
	                continue;
	            }

	                int  second= stack.pop();
	                int  first= stack.pop();
	                int ans = 0;
	                switch(element)
	                {
	                    case "+":
	                        ans = first + second;
	                        break;
	                    case "-":
	                            ans = first - second;
	                            break;
	                    case  "/":
	                            ans = first / second;
	                            break;

	                    case  "*":
	                            ans = first * second;
	                            break;

	                }    
	                stack.push(ans);
	        }
	        return stack.pop();
	    }
	}

Author: Akshay Ravindran

Algorithm👨‍🎓

  1. Create a Stack which will store the numbers in the reverse order.
  2. When you come across an operator. Pop the top two elements from the stack.
  3. I have used the second number as the first pop then I do not have to worry about changing the variables for subtraction and division separately because the order matters for those operations.
  4. Create a switch case which will act based on the **type **of the operator.
  5. For each switch case, perform their operations on the two variables and push the result into the stack again.
  6. At the end of the traversal, the element at the top of the stack is the result.🔚

#software-development #programming #java #interview #coding

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Buddha Community

How to evaluate Reverse Polish Notation?

How to evaluate Reverse Polish Notation?

Introduction🛹

Hey guys, Today is day 15 of the 100 Days to** LinkedIn Challenge.**

Image for post

Free For Kindle Readers

If you are Preparing for your Interview. Even if you are settled down in your job, keeping yourself up-to-date with the latest **Interview Problems **is essential for your career growth. Start your **prep **from Here!

Last month, I have been researching to find out the Frequently asked problems from these Companies. I have compiled **100 **of these questions, I am not promising you that you will get these questions in your interview but I am confident that most of these “interview questions” have similar logic and employs the same way of thinking from these set of challenges.

Before we move on to the first problem, If you are wondering why I chose LinkedIn, Yahoo and Oracle over FAANG is because I have completed a challenge Focusing on Amazon and Facebook Interview Questions in this Series:

New Day, New Strength, New Thoughts🚀

Day 15 — Reverse Polish Notation🏁

AIM🏹

Evaluate the value of an arithmetic expression in Reverse Polish Notation.

Valid operators are +-*/. Each operand may be an integer or another expression.

Note:

  • Division between two integers should truncate toward zero.
  • The given RPN expression is always valid. That means the expression would always evaluate to a result and there won’t be any divide by zero operation.

Example🕶

Input: ["2", "1", "+", "3", "*"]
Output: 9
Explanation: ((2 + 1) * 3) = 9

Input: ["4", "13", "5", "/", "+"]
Output: 6
Explanation: (4 + (13 / 5)) = 6

Code👇

	class Solution {
	    public int evalRPN(String[] tokens) {
	        Stack<Integer> stack = new Stack<Integer>();
	        for(String element : tokens)
	        {
	            if(!"+-*/".contains(element))
	            {
	                stack.push(Integer.valueOf(element));
	                continue;
	            }

	                int  second= stack.pop();
	                int  first= stack.pop();
	                int ans = 0;
	                switch(element)
	                {
	                    case "+":
	                        ans = first + second;
	                        break;
	                    case "-":
	                            ans = first - second;
	                            break;
	                    case  "/":
	                            ans = first / second;
	                            break;

	                    case  "*":
	                            ans = first * second;
	                            break;

	                }    
	                stack.push(ans);
	        }
	        return stack.pop();
	    }
	}

Author: Akshay Ravindran

Algorithm👨‍🎓

  1. Create a Stack which will store the numbers in the reverse order.
  2. When you come across an operator. Pop the top two elements from the stack.
  3. I have used the second number as the first pop then I do not have to worry about changing the variables for subtraction and division separately because the order matters for those operations.
  4. Create a switch case which will act based on the **type **of the operator.
  5. For each switch case, perform their operations on the two variables and push the result into the stack again.
  6. At the end of the traversal, the element at the top of the stack is the result.🔚

#software-development #programming #java #interview #coding

Jerod  Mante

Jerod Mante

1600287060

SQL REVERSE Function Example | SQL Server REVERSE()

SQL REVERSE() function is used for reversing the string. It accepts a string of characters as an argument and returns the reverse order of the string. The REVERSE is one of the  SQL String Functions, which is used to reverse the specified expression. The REVERSE() function reverses a string and returns the result.

SQL REVERSE Function

The REVERSE function is used to reverse the given string.

See the following syntax of the REVERSE function.

Syntax

SELECT REVERSE(string)

Parameters

String: It is the source string of which characters have to be reversed.

#sql #sql reverse #sql server reverse

Pam Facitlies

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A well polishing on marble floor is a process of restoration of old marble into new one. Your marble floor will look like a mirror shine finish after this process. Marble polishing is not simple as it seems by its name but it has a number of critical steps which require professional & experts manual efforts. If anyone will be missed out, then chances will be high of messy floors & scratches. We at PAM Facilities have well organized machines, branded material and more than 10 + years of team of experts which will take out marble’s original shine back with their efforts. For more details, Call us 9999710453 and 9958530555 or Floor Polishing Services in Delhi

#marble #polishing

Koire phili

Koire phili

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CARDANO BULLISH REVERSAL IN PLAY! (But Wait For THIS Confirmation)

Intro 00:00

Crypto market cap getting started 00:25

ADA vs. ETH and BTC 1:00

Cardano on weekly chart 2:00

What id ADA enters a bear market 3:00

Cardano daily bullish reversal soon? 5:20

Testing this bullish indicator in a bearish way 8:00

Be careful of this resistance 9:50

ADA price held support so far 10:20

What we want to see Cardano price do 11:40

Big short term resistance 12:20

Remember these ada dips happen a lot 12:40

Cardano price consolidating around the very important range of $1.50. We must watch carefully how ADA closes the weekly candle tomorrow. With a lot of resistance just above, do Cardano bulls have the momentum to break through? The momentum on the Cardano daily chart might just be lining up in a positive way. As always we wait for bullish confirmation and bearish confirmation in trying to identify bull market continuation or bear market beginning for this top crypto.
📺 The video in this post was made by Crypto Capital Venture
The origin of the article: https://www.youtube.com/watch?v=zmO0-pCcbmg
🔺 DISCLAIMER: The article is for information sharing. The content of this video is solely the opinions of the speaker who is not a licensed financial advisor or registered investment advisor. Not investment advice or legal advice.
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#bitcoin #blockchain #cardano #cardano bullish reversal #cardano bullish reversal in play #wait for this confirmation

Python reversed: How to Use reversed() Method in Python

The reversed() method returns the iterator that accesses the given sequence in the reverse order.

Python reversed()

Python reversed() is an inbuilt function that returns an  iterator that accesses the given sequence in the reverse order. The iter() function returns an iterator object. The  list.reverse() method reverses a List.

Syntax

reversed(seq)

#python #python reversed