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Commit 2c3676d

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author
tumanob
committed
Add problem 69 and minor cleaning of other tasks
1 parent e56e94d commit 2c3676d

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3 files changed

+69
-30
lines changed

3 files changed

+69
-30
lines changed
Lines changed: 38 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,38 @@
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package Sqrt_p69
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/**
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* https://leetcode.com/problems/sqrtx/
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* Given a non-negative integer x, compute and return the square root of x.
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* Since the return type is an integer, the decimal digits are truncated,
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* and only the integer part of the result is returned.
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*/
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object Solution {
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/**
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* I am gonna Use Newton's method to calculate it as it is fun
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* and used in many functional programing courses as a reference
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*
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* Some external reading about the method
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* https://blogs.sas.com/content/iml/2016/05/18/newtons-method-babylonian-square-root.html
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*/
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val tolerance = 0.001 // when it is good enough as well a start guess
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def mySqrt(x: Int): Int = {
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def isGoodEnough(guess: Double): Boolean =
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Math.abs(guess * guess - x) < tolerance
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def improve(guess: Double): Double =
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(guess + x / guess) * 0.5
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def iterator(guess: Double): Double =
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if (isGoodEnough(guess)) guess
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else iterator(improve(guess))
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iterator(tolerance).toInt
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}
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def main(args: Array[String]): Unit = {
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println(mySqrt(3)) // 1
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println(mySqrt(4)) // 2
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println(mySqrt(8)) // 2
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}
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}

‎ScalaSolutions/src/main/scala/TwoSum_p1/Solution.scala

Lines changed: 6 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -11,13 +11,6 @@ package TwoSum_p1
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*/
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object Solution {
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def main(args: Array[String]): Unit = {
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println(twoSum(Array(2,7,11,15), 18).mkString("[", ",", "]")) // [1,2]
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println(twoSum(Array(2,7,11,15), 9).mkString("[", ",", "]")) // [0,1]
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println(twoSum(Array(2,7,11,15), 26).mkString("[", ",", "]")) // [2,3]
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}
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//leetcode submit region begin(Prohibit modification and deletion)
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def twoSum(nums: Array[Int], target: Int): Array[Int] = {
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def twoSum(index: Int, previous: Map[Int, Int]): Array[Int] = {
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previous.get(target - nums(index)) match {
@@ -27,5 +20,10 @@ object Solution {
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}
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twoSum(0, Map.empty)
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}
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//leetcode submit region end(Prohibit modification and deletion)
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def main(args: Array[String]): Unit = {
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println(twoSum(Array(2,7,11,15), 18).mkString("[", ",", "]")) // [1,2]
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println(twoSum(Array(2,7,11,15), 9).mkString("[", ",", "]")) // [0,1]
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println(twoSum(Array(2,7,11,15), 26).mkString("[", ",", "]")) // [2,3]
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}
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}

‎ScalaSolutions/src/main/scala/ValidParentheses_p20/Solution.scala

Lines changed: 25 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -14,9 +14,32 @@ import scala.collection.mutable.Stack
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*/
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object Solution {
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import scala.collection.mutable.Stack
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val stack = new Stack[Char]()
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val OpenToClose: Map[Char, Char] = Map('{' -> '}', '[' -> ']', '(' -> ')')
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def checkPar(char: Char): Boolean =
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if (OpenToClose.contains(char)) {
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stack.push(char)
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true
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} else if (stack.size > 0 && OpenToClose.get(stack.top) == Some(char)) {
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stack.pop()
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true
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} else {
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false
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}
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def isValid(s: String): Boolean = {
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stack.clear()
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s.size > 0 && // check edge case for empty string
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s.forall(checkPar) && // run validation agains string elements
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stack.size == 0 // if after check stack is not empty this is fail case
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}
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def main(args: Array[String]): Unit = {
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println(!isValid("["))
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println(isValid("()[]{}")) // all should be true
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println(!isValid("["))// all should be true
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println(isValid("()[]{}"))
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println(isValid("()"))
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println(!isValid("(]"))
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println(isValid("[()]"))
@@ -26,24 +49,4 @@ object Solution {
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println(!isValid("{{[](A}}}}"))
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println(!isValid("{[(])}"))
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}
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def isValid(s: String): Boolean = {
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import scala.collection.mutable.Stack
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val stack = new Stack[Char]()
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val OpenToClose: Map[Char, Char] = Map('{' -> '}', '[' -> ']', '(' -> ')')
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def checkPar(char: Char): Boolean = {
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if (OpenToClose.contains(char)) {
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stack.push(char)
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true
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} else if (stack.size > 0 && OpenToClose.get(stack.top) == Some(char)) {
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stack.pop()
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true
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} else {
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false
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}
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}
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s.size > 0 && s.forall(checkPar) && stack.size == 0
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}
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}

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