DEV Community: Sivakumar Mathiyalagan

Exercise python

Sivakumar Mathiyalagan — Mon, 15 Jun 2026 05:17:57 +0000

Two numbers are said to be amicable numbers if the sum of the factors of one number (except the number itself) gives the other number.
The numbers 220 and 284 are amicable, since the sum of the factors of 220 (except 220)

Check whether 1184 and 1210 are amicable numbers.

num1 = 1184
num2 = 1210

def sumOfFactor (num):
    divisor = 2
    sum = 1
    while divisor <= num//2:
        if num%divisor == 0:
            sum = sum + divisor
        divisor+=1
    return sum


if sumOfFactor(num1) == sumOfFactor(num2):
    print (sumOfFactor(num1), "is amicable to",sumOfFactor(num2))
else:
    print (sumOfFactor(num1), "is not amicable to",sumOfFactor(num2))

A book seller has 175 English books, 245 Science books and 385 Mathematics books. He wants to sell the books in a box, subject-wise in equal numbers. What will be the greatest number of the boxes required? Also find the number of books for each subject
in a box.

english = 175
science = 245
maths = 385
hcf = 0
divisor = 2

while divisor < maths//2:
    if(english%divisor==0 and science%divisor==0 and maths%divisor==0):
        hcf = divisor
    divisor+=1

englishBooks = english // hcf
scienceBooks = science // hcf
mathsBooks = maths // hcf

print("no of boxes required is", hcf, "and no of books in each box to be", "English-books",englishBooks, "Science-books",scienceBooks,"Maths-books", mathsBooks)

python-exercises

Sivakumar Mathiyalagan — Fri, 12 Jun 2026 14:58:05 +0000

# smallest four digit prime number


def find_prime(no):
    div = 2
    divisors_count = 0

    while div <= no//2:
        if no % div == 0:
            divisors_count += 1
        div += 1

    return divisors_count == 0

givenNumber = 1000

while givenNumber >= 1000:
    if (find_prime(givenNumber)):
        print("smallest prime number", givenNumber)
        break
![ ](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/8uc0afb1lvycntrath2t.png)
    givenNumber = givenNumber+1

# Write the smallest and the Largest two digit prime number

givenNumber = 100
start = 10

while start < givenNumber:
    if (find_prime(start)):
        print("smallest prime number", start)
        break
    start = start+1

while givenNumber > start:
    if(find_prime(givenNumber)):
        print("largest prime number", givenNumber)
        break
    givenNumber = givenNumber - 1

# I am a two digit prime number and the sum of my digits is 10. I am also one of the factors of 57. Who am I?

def find_prime(no):
    div = 2
    divisors_count = 0

    while div <= no//2:
        if no % div == 0:
            divisors_count += 1
        div += 1

    return divisors_count == 0

start = 10


while start < 100:
    if (find_prime(start)):
        sum =0
        sum = sum + start % 10 + start // 10
        if(sum ==10 and  57 % start == 0):
            print("i am that two digit number",start)
            break
    start = start+1

python-exercise

Sivakumar Mathiyalagan — Thu, 11 Jun 2026 14:32:18 +0000

# print 34 23 12

givenNumber = 342312

while givenNumber > 0:
    print (givenNumber % 100)
    givenNumber = givenNumber // 100

# print 34 12

givenNumber = 342312

print (givenNumber % 100)
print (givenNumber//10000)

# print  sum of 34 23 12

givenNumber = 342312

while givenNumber > 0:
    num = (givenNumber % 100)
    sum = 0
    while num > 0:

        sum = sum + num % 10
        num = num//10
    print(sum)
    givenNumber = givenNumber//100

#  print sum of  34 12

givenNumber = 342312

num = givenNumber % 100
num2 = givenNumber//10000
sum = 0
while num > 0:
    sum = sum + num % 10
    num = num//10
print(sum)
sum = 0
while num2 > 0:
    sum = sum + num2 % 10
    num2 = num2//10
print(sum)

# Task5: given number 123456 --> 456 123

givenNumber = 123456

print(givenNumber % 1000)
print (givenNumber // 1000)

Check Divisibility - Python

Sivakumar Mathiyalagan — Wed, 10 Jun 2026 04:40:22 +0000

# divisible by 11

num = 135802467913580246790
val1 = 0
val2 = 0


while num > 0:

    total = num % 100
    val1 = val1 + total % 10
    val2 = val2 + total // 10

    num = num//100

if (val1 - val2) % 11 == 0:
    print("divisible by 11")
else:
    print("not divisible by 11")

# divisible by 2

num = 135802467913580246790

value = num%10

if value % 2 == 0:
    print("divisible by 2")
else:
    print("Not divisible by 2")

# divisible by 3

num = 135802467913580246790  
sum = 0

while num > 0:
    sum = sum + num % 10
    num = num // 10

if sum % 3 == 0:
    print("divisible by 3")
else:
    print("not divisible by 3")

# divisible by 5
num = 135802467913580246790

value = num%10

if value == 0 or value == 5:
    print("divisible by 5")
else:
    print("Not divisible by 5")

# divisible by 4

num = 135802467913580246790

value = num%100

if value % 4 == 0:
    print("divisible by 4")
else:
    print("Not divisible by 4")

# divisible by 6

num = 135802467913580246790

value = num%10

sum = 0

while num > 0:
    sum = sum + num % 10
    num = num // 10

if value % 2 == 0 and sum % 3 == 0:
      print("divisible by 6")
else:
    print("Not divisible by 6")

# divisible by 8

num = 135802467913580246790

value = num%1000

if value % 8 == 0:
    print("divisible by 8")
else:
    print("Not divisible by 8")

# divisible by 9

num = 135802467913580246790  
sum = 0

while num > 0:
    sum = sum + num % 10
    num = num // 10

if sum % 9 == 0:
    print("divisible by 9")
else:
    print("not divisible by 9")

# divisible by 10

num = 135802467913580246790

value = num%10

if value == 0:
    print("divisible by 10")
else:
    print("Not divisible by 10")

Python-Exercise

Sivakumar Mathiyalagan — Sat, 06 Jun 2026 08:21:41 +0000

CODE

# print [1 1 1 1 1]

count = 0
i = 5

while count < i:
    print ("1" ,end=" ")
    count = count+1



# print [1 2 3 4 5]

count = 1
i = 5

while count <= i:
    print (count ,end=" ")
    count = count+1



# print [1 3 5 7 9]

count = 1
i = 10

while count < i:
    print (count ,end=" ")
    count = count+2



# print [3 6 9 12 15]

count = 1
i = 5

while count <= i:
    print (count * 3 ,end=" ")
    count = count+1


# print [15 12 9 6 3]

count = 5
i = 1

while count >= i:
    print (count * 3 ,end=" ")
    count = count-1



# print [10 8 6 4 2]

count = 5
i = 1

while count >= i:
    print (count * 2 ,end=" ")
    count = count-1



# print [9 7 5 3 1]

count = 9
i = 1

while count >= i:
    print (count ,end=" ")
    count = count-2



# print Multiples of 3 and 5

max = 100
start = 1

while start <= max:
    if start % 3 == 0 and start % 5 == 0:
        print (start)
    start = start + 1   



#  print Multiples of 3 or 5

max = 100
start = 1

while start <= max:
    if start % 3 == 0 or start % 5 == 0:
        print (start)
    start = start + 1  



# print the divisors of given number

givenNumber = 25
start = 1

while start <= givenNumber:
    if givenNumber % start == 0:
        print (start)
    start+=1



# count the divisors of given number

givenNumber = 25
start = 1
total = 0

while start <= givenNumber:
    if givenNumber % start == 0:
        total += 1
    start+=1

print(total)



# check for perfect number

givenNumber = 498
start = 1
total = 0

while start < givenNumber:
    if givenNumber % start == 0:
       total = total + start
    start += 1 

if total == givenNumber:
    print("perfect number")
else :
    print ("not a perfect number")



# print [1 3 5 7 9 2 4 6 8 10]

count = 1

while count <= 10:
    if count <= 5:
        print(2 * count - 1, end=" ")
    else:
        print(2 * (count - 5), end=" ")
    count += 1




# factorial of given number

givenNumber = 4
total = 1

while givenNumber >= 1:
    total = total * givenNumber
    givenNumber -= 1
print (total)




# sum of first n numbers

givenNumber = 5
total = 0

while givenNumber >= 1:
    total = total + givenNumber
    givenNumber -= 1
print (total)


# print first five prime number

givenNumber = 25
start = 1
total = 0

while start <= givenNumber and total < 5:
    newStart = 1
    count = 0

    while newStart <= start:
        if start % newStart == 0:
            count += 1
        newStart +=1

    if count == 2:
        print(start)
        total += 1

    start +=1



# print sum of first five prime number

givenNumber = 100
start = 50
total = 0
primeTotal = 0

while start <= givenNumber and total < 5:
    newStart = 1
    count = 0

    while newStart <= start:
        if start % newStart == 0:
            count += 1
        newStart +=1

    if count == 2:
        primeTotal = primeTotal + start
        total += 1

    start +=1

print(primeTotal)

OUTPUT

useReducer - React

Sivakumar Mathiyalagan — Fri, 05 Jun 2026 04:06:20 +0000

useReducer:

useReducer is a React Hook used to manage complex state logic in your components. It is often described as a more powerful alternative to useState, particularly when the next state depends on the previous one or when you have multiple related state values that need to change together.

Syntax:

const [state, dispatch] = useReducer(reducer, initialArg, init?)

Reference:

reducer: The reducer function that specifies how the state gets updated. It must be pure, should take the state and action as arguments, and should return the next state. State and action can be of any types.

initialArg: The value from which the initial state is calculated. It can be a value of any type. How the initial state is calculated from it depends on the next init argument

optional init: The initializer function that should return the initial state. If it’s not specified, the initial state is set to initialArg. Otherwise, the initial state is set to the result of calling init(initialArg)(TBD)

dispatch: The dispatch function returned by useReducer lets you update the state to a different value and trigger a re-render. You need to pass the action as the only argument to the dispatch function

state: It holds the initial value and changes the value accordingly when the dispatch function executes

Code:

import React from "react";
import { useReducer } from "react";

function Counter(){


    function counterReducer(state,action){
        switch (action.type) {
            case "Increment" :
                return {count : state.count + 1}
            case "Decrement" :
                return {count : state.count - 1}   
            case "Reset" :
                return {count : 0}     
        }
    }

    const [state,dispatch] = useReducer(counterReducer,{count : 0})

    return(
        <>
        <h1>{state.count}</h1>
        <button onClick={()=>dispatch({type:"Increment"})}>Increment</button>
        <button onClick={()=>dispatch({type:"Decrement"})}>Decrement</button>
        <button onClick={()=>dispatch({type:"Reset"})}>Reset</button>
        </>
    )
}

  export default Counter

Output:

Python - looping series 3

Sivakumar Mathiyalagan — Mon, 01 Jun 2026 04:22:48 +0000

Count of Prime Numbers between 2 and 100

code

givenNumber = 100
startFrom = 2
total = 0

while startFrom <= givenNumber:

    iterateFrom = 1
    count = 0

    while iterateFrom <= startFrom:

        if startFrom % iterateFrom == 0:
            count+=1

        iterateFrom = iterateFrom + 1

    if count == 2:
        total = total + 1


    startFrom = startFrom + 1

print (total)

output

Sum of Prime Numbers

code

givenNumber = 100
startFrom = 2
total = 0

while startFrom <= givenNumber:

    iterateFrom = 1
    count = 0

    while iterateFrom <= startFrom:

        if startFrom % iterateFrom == 0:
            count+=1

        iterateFrom = iterateFrom + 1

    if count == 2:
        total = total + startFrom


    startFrom = startFrom + 1

print (total)

output

Count of Prime Numbers 25 and 50

code

ivenNumber = 100
startFrom = 2
total = 0

while startFrom <= givenNumber:

    iterateFrom = 1
    count = 0

    while iterateFrom <= startFrom:

        if startFrom % iterateFrom == 0:
            count+=1

        iterateFrom = iterateFrom + 1

    if count == 2 and startFrom > 24 and startFrom < 51:
        total = total + startFrom


    startFrom = startFrom + 1

print (total)

output

Count of single digit prime numbers

code

givenNumber = 100
startFrom = 2
total = 0

while startFrom <= givenNumber:

    iterateFrom = 1
    count = 0

    while iterateFrom <= startFrom:

        if startFrom % iterateFrom == 0:
            count+=1

        iterateFrom = iterateFrom + 1

    if count == 2 and startFrom < 10:
        total = total + startFrom


    startFrom = startFrom + 1

print (total)

output

Python Exercise

Sivakumar Mathiyalagan — Sat, 30 May 2026 06:56:18 +0000

Question:
Given an integer n, return all unique pairs of prime numbers whose sum is equal to n.

CODE:

givenNumber = 70
no2 = 1

while no2 < givenNumber:

    no1 = givenNumber - no2

    num = 1
    count1 = 0

    while num <= no1:
        if no1 % num == 0:
            count1 +=1
        num = num + 1


    num = 1
    count2 = 0

    while num <= no2:
         if no2 % num == 0:
             count2 +=1
         num = num + 1

    if count1 == 2 and count2 ==  2:
         print (no1,no2)


    no2 = no2 + 1

OUTPUT:

Looping in python-2

Sivakumar Mathiyalagan — Wed, 27 May 2026 06:30:58 +0000

Question :
_Two friends are driving separate trains from Chennai to Coimbatore.

Driver 1 drives Train 1, which stops at every 3rd station, while Driver 2 drives Train 2, which stops at every 5th station. There are a total of 30 stops between Chennai and Coimbatore.

Since the two drivers are friends, they want to know at which station they will meet for the first time during their journey.

Write a Python program to determine the first stop where both trains stop together_

Code:

train1 = 3
train2 = 5

totalStops = 30
stopCovered = 1

while stopCovered <= totalStops:

    if stopCovered % train1 == 0 and stopCovered % train2 == 0:
        print(stopCovered)
        break

    stopCovered = stopCovered + 1

Output:

Question :
_A thief snatched a purse and started running at a speed of 2 feet per step. A police officer saw the incident and began chasing the thief at a speed of 5 feet per step. At the beginning of the chase, the thief already had a lead of 40 feet.

Write a Python program to determine how many feet the police officer must cover to catch the thief._

Code:

police = 5
thief = 2

thiefCovered = 40
policeCovered =0

while policeCovered <= thiefCovered:
    policeCovered= policeCovered + police
    thiefCovered = thiefCovered + thief

print(policeCovered)

output:

Looping in Python

Sivakumar Mathiyalagan — Wed, 27 May 2026 06:03:36 +0000

Question:
_A priest plucked some flowers from his garden and started visiting temples on his way home. He visited 7 temples in total. At each temple, he offered half of the flowers he had at that moment. After visiting all 7 temples and returning home, he was left with exactly one flower in his hand.

How many flowers did he originally pluck from his garden?_

Code:

flowers = 1
temples = 7
while temples > 0:
    temples = temples -1
    flowers = flowers*2


print (flowers)

Output:

Question:
_After being banned from the royal court, Tenali Raman cleverly bribed his way in to meet Krishnadevaraya.

The king, angry at Tenali’s actions, ordered a punishment of 512 belt beatings. Before entering the court, Tenali had made a deal with each security guard he bribed to share half of whatever reward he received from the king.

Following the agreement, every guard took half of the remaining punishment, one after another. In the end, Tenali returned home without receiving a single beating.

How many security guards did Tenali bribe?_

Code:

beatings = 512
security = 0

while beatings>0:
    beatings =  beatings//2
    security = security+1

print(security)

Output:

Flow Chart

Sivakumar Mathiyalagan — Tue, 26 May 2026 06:30:12 +0000

CODE

feet = 50
days = 0
up = 2
down = 1

while feet > 0:
    feet = feet - up + down
    days += 1

print("Days:", days)

FLOW CHART

CODE

result = 0
no = 1

while no <= 5:
    result = result + no
    no += 1

print(result)

FLOW CHART

CODE

result = 1
no = 5

while no >= 1:
    result = result * no
    no -= 1

print(result)

FLOW CHART

UseEffect - Exercises

Sivakumar Mathiyalagan — Fri, 22 May 2026 07:15:44 +0000

Render only once using UseEffect

import { useEffect, useState } from "react";

function Input(){

    const[name,setName] = useState('')

    useEffect(()=>console.log("Component Mounted"),[]);



    return(
    <>
      <input value={name} type="text" onChange={(e)=>setName(e.target.value)}></input>
        <p>Hi! Welcome {name}</p>
        </>

    )

}

export default Input

Output:

Note:
React is running in Strict Mode during development
React intentionally mounts, unmounts, and remounts components once in development to detect side effects. Because of that, it is printed twice in console, this happens only in development mode but in production build, it runs once

Render Every time using UseEffect

import { useEffect, useState } from "react";

function Input(){

    const[name,setName] = useState('')

    useEffect(()=>console.log("Component Mounted"));



    return(
    <>
      <input value={name} type="text" onChange={(e)=>setName(e.target.value)}></input>
        <p>Hi! Welcome {name}</p>
        </>

    )

}

export default Input

Output:

Render Only when State changes using UseEffect

import { useEffect, useState } from "react";

function Input(){

    const[name,setName] = useState('')

    useEffect(()=>console.log("Component Mounted"),[name]);



    return(
    <>
      <input value={name} type="text" onChange={(e)=>setName(e.target.value)}></input>
        <p>Hi! Welcome {name}</p>
        </>

    )

}

export default Input

Output:

Note:
State Variable name is updated 4 times so the useEffect re-rendered 4 times the call back function

Two States and One Effect
Effect runs when count or name is changed

import { useEffect, useState } from "react";

function Input(){

    const[name,setName] = useState('')
    const[count,setCount]=useState(0)

    useEffect(()=>console.log("Component Mounted"),[name,count]);



    return(
    <>
      <input value={name} type="text" onChange={(e)=>{setName(e.target.value)
       }
      }></input>
      <button value={count} onClick={(e)=>{
        setCount(count+1)}
      }>+</button>
        <p>Hi! Welcome {name} and  Count {count}</p>
        </>

    )

}

export default Input

Output

Note:
State variable name is updated thrice and so effect ran thrice
State variable count is updated thrice and so effect ran thrice for it as well

*Show Even only when count becomes Even *

import { useEffect, useState } from "react";

function Input(){

    const[name,setName] = useState('')
    const[count,setCount]=useState(0)

    useEffect(()=>{
      if(count%2===0){
        console.log("even")
      }
    },[count]);



    return(
    <>
      <input value={name} type="text" onChange={(e)=>{setName(e.target.value)
       }
      }></input>
      <button value={count} onClick={(e)=>{
        setCount(count+1)}
      }>+</button>
        <p>Hi! Welcome {name} and  Count {count}</p>
        </>

    )

}

export default Input

Output

Note:
count is incermented 16 times and even is printed on console only 8 times for even counts only