The Programming Project

Monday, January 23, 2023

Leet Code Two Sum

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.
You can return the answer in any order.
 
Example 1:
Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
Example 2:
Input: nums = [3,2,4], target = 6
Output: [1,2]
Example 3:
Input: nums = [3,3], target = 6
Output: [0,1]
 
Constraints:
2 <= nums.length <= 104
-109 <= nums[i] <= 109
-109 <= target <= 109
Only one valid answer exists.


class Solution(object):
    def twoSum(self, nums, target):
        output = []
        flag = False
        for i in range(len(nums)):
            for j in range (i+1,len(nums)):
                if nums[i]+nums[j] == target:
                    output.append(i)
                    output.append(j)
                    flag = True
                    break
            if flag == True:
                break
        print(output)
        #return(output)
obj = Solution()
nums = []
target = int(input("Enter the target element:"))
n = int(input("Enter the number of elements in the array:"))
for i in range(n):
    nums.append(int(input("Enter an element:")))
print(nums)
obj.twoSum(nums,target)

Sunday, January 22, 2023

Leet Code Integer to Roman

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             1000

For example, 2 is written as II in Roman numeral, just two ones added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II.

Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used:

I can be placed before V (5) and X (10) to make 4 and 9.
X can be placed before L (50) and C (100) to make 40 and 90.
C can be placed before D (500) and M (1000) to make 400 and 900.

Given a roman numeral, convert it to an integer

Example 1:

Input: s = "III"
Output: 3
Explanation: III = 3.

Example 2:

Input: s = "LVIII"
Output: 58
Explanation: L = 50, V= 5, III = 3.

Example 3:

Input: s = "MCMXCIV"
Output: 1994
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.

Constraints:

1 <= s.length <= 15
s contains only the characters ('I', 'V', 'X', 'L', 'C', 'D', 'M').
It is guaranteed that s is a valid roman numeral in the range [1, 3999].

Python Code

class Solution(object):

    def intToRoman(self, numb):
        temp = numb
        list_digits = []

        while temp > 0:
            list_digits.append(temp % 10)
            temp = int(temp / 10)
            self.numberlength += 1
        if self.numberlength == 4:
            for i in range(list_digits[3]):
                self.output += "M"
            self.numberlength -= 1
        if self.numberlength == 3:
            self.numberlength -= 1
            if list_digits[2] * 100 == 400 or list_digits[2] * 100 == 900:
                self.output += self.exceptionSymbols[self.position(
                    list_digits[2] * 100)]
            else:
                if list_digits[2] * 100 == 500:
                    self.output += "D"
                elif list_digits[2] * 100 == 800:
                    self.output += "DCCC"
                elif list_digits[2] * 100 == 700:
                    self.output += "DCC"
                elif list_digits[2] * 100 == 600:
                    self.output += "DC"
                elif list_digits[2] * 100 == 300:
                    self.output += "CCC"
                elif list_digits[2] * 100 == 200:
                    self.output += "CC"
                elif list_digits[2] * 100 == 100:
                    self.output += "C"
                else:
                    self.output += ""
        if self.numberlength == 2:
            self.numberlength -= 1
            if list_digits[1] * 10 == 40 or list_digits[1] * 10 == 90:
                self.output += self.exceptionSymbols[self.position(
                    list_digits[1] * 10)]
            else:
                if list_digits[1] * 10 == 50:
                    self.output += "L"
                elif list_digits[1] * 10 == 80:
                    self.output += "LXXX"
                elif list_digits[1] * 10 == 70:
                    self.output += "LXX"
                elif list_digits[1] * 10 == 60:
                    self.output += "LX"
                elif list_digits[1] * 10 == 30:
                    self.output += "XXX"
                elif list_digits[1] * 10 == 20:
                    self.output += "XX"
                elif list_digits[1] * 10 == 10:
                    self.output += "X"
                else:
                    self.output += ""
        if self.numberlength == 1:
            self.numberlength -= 1
            if list_digits[0] == 4 or list_digits[0] == 9:
                self.output += self.exceptionSymbols[self.position(
                    list_digits[0])]
            elif list_digits[0] == 5:
                self.output += "V"
            elif list_digits[0] == 8:
                self.output += "VIII"
            elif list_digits[0] == 7:
                self.output += "VII"
            elif list_digits[0] == 6:
                self.output += "VI"
            elif list_digits[0] == 3:
                self.output += "III"
            elif list_digits[0] == 2:
                self.output += "II"
            elif list_digits[0] == 1:
                self.output += "I"
            else:
                self.output += ""
        return self.output

    def position(self, symb):
        counter = 0
        while symb != self.exceptionValues[counter]:
            counter += 1
        return (counter)

    def __init__(self) -> None:
        self.exceptionValues = [4, 9, 40, 90, 400, 900]
        self.exceptionSymbols = ["IV", "IX", "XL", "XC", "CD", "CM"]
        #self.symbol = ['I', 'V', 'X', 'L', 'C', 'D', 'M']
        #self.value = [1, 5, 10, 50, 100, 500, 1000]
        self.output = ""
        self.numberlength = 0


obj = Solution()
num = int(input("Enter an integer range(1,3999):"))
print(obj.intToRoman(num))

Saturday, January 21, 2023

Karl Pearson Coefficient of Correlation and Scatter diagram Regression Line

A simple program to calculate the correlation between two variates (X and Y) and the Karl Pearson Coefficient of correlation. The scatter diagram along with the regression line of Y on X has been plotted.

import matplotlib.pyplot as plt
import numpy as np
import math


class RegressionLine:

    def plotScatterDiagram(self):
        x = np.array(self._xValues)
        y = np.array(self._yValues)
        plt.scatter(x, y)
        # calculating regression of y on x
        self._bYX = (self._karlPCoefficient*self._sigmaY)/self._sigmaX
        self._bXY = (self._karlPCoefficient*self._sigmaX)/self._sigmaY
        x = np.linspace(self._minX,self._maxX,100)
        y = (self._bYX)*x + (self._sumY/self._N - (self._sumX/self._N)*self._bYX )
        plt.title('Regression line of y on x')
        plt.plot(x, y, '-r', label='regression line of y on x')
        plt.xlabel('x', color='#1C2833')
        plt.ylabel('y', color='#1C2833')
        plt.show()
    def parityString(self, string):
        while len(string) < 9:
            string += " "
        return string

    def accept(self):
        self._N = int(input("Enter the total number of values:"))
        print("Enter the data for x and y:")
        for i in range(self._N):
            print("Enter the value at position ", (i + 1))
            self._xValues.append(float(input("Enter a x value: ")))
            self._yValues.append(float(input("Enter a y value: ")))
        print("Enter 0 is you don't want a change of scale:")
        self._A = float(input("Enter the assumed mean for x-data set:"))
        self._B = float(input("Enter the assumed mean for y-data set:"))

    def calculateCovariance(self):
        for i in range(self._N):
            if self._maxX < self._xValues[i]:
                self._maxX = self._xValues[i]
            if self._minX > self._xValues[i]:
                self._minX = self._xValues[i]
            self._uValues.append(self._xValues[i] - self._A)
            self._vValues.append(self._yValues[i] - self._B)
            self._uvValues.append(self._uValues[i] * self._vValues[i])
            self._sumXY += self._uvValues[i]
            self._sumX += self._uValues[i]
            self._sumY += self._vValues[i]
        self._coVarianceXY = (1 / self._N) * (
            self._sumXY - (1 / self._N) * self._sumX * self._sumY)
        # print covariance table
        if self._A == 0 and self._B == 0:
            print(self.parityString("X"), self.parityString("Y"),
                  self.parityString("XY"))
            for i in range(self._N):
                print(self.parityString(str(self._xValues[i])),
                      self.parityString(str(self._yValues[i])),
                      self.parityString(str(self._uvValues[i])))
            print("-------------------------------------")
            print(self.parityString(str(self._sumX)),
                  self.parityString(str(self._sumY)),
                  self.parityString(str(self._sumXY)))
            print("-------------------------------------")
            print("Cov(X,Y)=", self._coVarianceXY)
        else:
            print(self.parityString("X"), self.parityString("u"),
                  self.parityString("Y"), self.parityString("v"),
                  self.parityString("uv"))
            for i in range(self._N):
                print(self.parityString(str(self._xValues[i])),
                      self.parityString(str(self._uValues[i])),
                      self.parityString(str(self._yValues[i])),
                      self.parityString(str(self._vValues[i])),
                      self.parityString(str(self._uvValues[i])))
            print("-----------------------------------------------")
            print(self.parityString(" "), self.parityString(str(self._sumX)),
                  self.parityString(" "), self.parityString(str(self._sumY)),
                  self.parityString(str(self._sumXY)))
            print("-----------------------------------------------")
            print("Cov(X,Y)=", self._coVarianceXY)

    def calculateKarlPearson(self):
        self._sigmaX = self.calculateSD(self._uValues)
        self._sigmaY = self.calculateSD(self._vValues)
        self._karlPCoefficient = self._coVarianceXY / (self._sigmaX *
                                                       self._sigmaY)
        print("r =", round(self._karlPCoefficient, 3))

    def calculateSD(self, _valuesList):
        standard_deviation = 0.0
        mean = 0
        for i in range(self._N):
            mean += _valuesList[i]
        mean /= self._N
        for i in range(self._N):
            standard_deviation += (_valuesList[i] - mean)**2
        standard_deviation /= self._N
        standard_deviation = math.sqrt(standard_deviation)
        return standard_deviation

    def __init__(self) -> None:
        self._xValues = []
        self._uValues = []
        self._yValues = []
        self._vValues = []
        self._uvValues = []
        self._coVarianceXY = 0.0
        self._karlPCoefficient = 0.0
        self._sigmaX = 0.0  # standard deviation for X
        self._sigmaY = 0.0  # standard deviation for Y
        self._N = 0
        self._A = 0  # assumed mean for X
        self._B = 0  # assumed mean for Y
        self._maxX = float('-inf')
        self._minX = float('inf')
        self._sumX = 0
        self._sumY = 0
        self._sumXY = 0
        self._bYX = 0
        self._bXY = 0

obj = RegressionLine()
obj.accept()
obj.calculateCovariance()
obj.calculateKarlPearson()
obj.plotScatterDiagram()

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