1. Create separate class(java file) for each problem
2. Test your solution with few examples in main method
3. Try to avoid writing logic in the main method, create separate method for the logic to execute
4. Create different folder for problems for each assignment
5. Try to include edge cases in your logic
Q1) Create a Shape class and two sub classes Rectangle and Square Shape :
Fields : name, color, area, perimeter
Constructors :
Shape(name, color)
Shape(name, color, perimeter, area)
Methods : printShape() Rectangle: Inherits Shape Fields : width, height
Constructors:
Rectangle(side)→If single side is given then set width and height to same value. Rectangle(width, height)
Rectangle(name, color, width, height)
Square: Inherits Shape Fields: side
Constructors: Square(side) Square(name, color, side)
- 1) Create getter and setter methods for all classes.
- 2) Create printShape() method in Shape class that returns desired string output.
- 3) Override the getArea() and getPerimeter() getter methods of Shape in Rectangle and
Square to give desired output.
4)Use the Shape tester class to test your classes.
public class ShapeTester {
public static void main(String[] args) {
Shape shape1 = new Shape(“Shape1”, “pink”); System.out.println(“shape1”); System.out.println(shape1.printShape());
Shape shape2 = new Shape(“Shape2”, “orange”, 20, 30);
System.out.println(“shape2”);
System.out.println(“area : ” + shape2.getArea() + ” perimeter : ” + shape2.getPerimeter()); System.out.println(shape2.printShape());
Rectangle rectangle1 = new Rectangle(2);
System.out.println(“rectangle1”);
System.out.println(“area : ” + rectangle1.getArea() + ” perimeter : ” + rectangle1.getPerimeter());
Rectangle rectangle2 = new Rectangle(“Rectangle”, “Purple”,4, 7); System.out.println(“rectangle2”);
System.out.println(“area : ” + rectangle2.getArea() + ” perimeter : ” + rectangle2.getPerimeter()); System.out.println(rectangle2.printShape());
Square square1 = new Square(3);
System.out.println(“square1”);
System.out.println(“area : ” + square1.getArea() + ” perimeter : ” + square1.getPerimeter());
Square square2 = new Square(“Square” , “black”, 7);
System.out.println(“square2”);
System.out.println(“area : ” + square2.getArea() + ” perimeter : ” + square2.getPerimeter()); System.out.println(square2.printShape());
} }
Output:
shape1 The Shape1 has a pink color shape2 |
area : 30 perimeter : 20 The Shape2 has a orange color rectangle1 area : 4 perimeter : 8 rectangle2 area : 28 perimeter : 22 The Rectangle has a Purple color square1 area : 9 perimeter : 12 square2 area : 49 perimeter : 28 The Square has a black color |
Q2) Create a Sum class with methods to get desired output. Use the below function to test the output.
public static void main(String[] args){
Sum sum = new Sum();
System.out.println(sum.add(2, 3)); //output : 5 System.out.println(sum.add(4, 9, 12));//output : 25 System.out.println(sum.add(4, 5.0));//output : 9.0 System.out.println(sum.add(15.5, 5));//output : 20.5 System.out.println(sum.add(1.0, 6.4));//output : 7.4
}
LeetCode :
1) Transpose Matrix : https://leetcode.com/problems/transpose-matrix/
Given a 2D integer array matrix, return the transpose of matrix.
The transpose of a matrix is the matrix flipped over its main diagonal, switching the matrix’s row and
column indices.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [[1,4,7],[2,5,8],[3,6,9]]
Example 2:
Input: matrix = [[1,2,3],[4,5,6]] Output: [[1,4],[2,5],[3,6]]
Constraints:
• •
• • •
m == matrix.length
n == matrix[i].length
1 <= m, n <= 1000
1 <= m * n <= 105
-109 <= matrix[i][j] <= 109
2) Shortest Word Distance : https://leetcode.com/problems/sign-of-the-product-of-an- array/
Given an array of strings and two different strings that already exist in the array word1 and word2, return the shortest distance between these two words in the list.
Example 1:
wordsDict
Input: wordsDict = [“practice”, “makes”, “perfect”, “coding”, “makes”], word1 = “coding”, word2 = “practice”
Output: 3
Example 2:
Input: wordsDict = [“practice”, “makes”, “perfect”, “coding”, “makes”], word1 = “makes”, word2 = “coding”
Output: 1
Constraints:
•
•
• consists of lowercase English letters. • word1 and word2 are in wordsDict.
•
1 <= wordsDict.length <= 3 * 104
1 <= wordsDict[i].length <= 10
wordsDict[i]
word1 != word2
3) Move Zeroes : https://leetcode.com/problems/move-zeroes/
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Given an integer array nums, move all 0’s to the end of it while maintaining the relative order of the non-zero elements. Note that you must do this in-place without making a copy of the array. |
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Example 1: |
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Input: nums = [0,1,0,3,12] Output: [1,3,12,0,0] |
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Example 2: |
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Input: nums = [0] Output: [0] |
Constraints:
• •
1 <= nums.length <= 104
-231 <= nums[i] <= 231 – 1
4) Rotate Image – https://leetcode.com/problems/rotate-image/
You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees
(clockwise).
You have to rotate the image in-place, which means you have to modify the input 2D matrix
directly. DO NOT allocate another 2D matrix and do the rotation.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [[7,4,1],[8,5,2],[9,6,3]]
Example 2:
Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]] Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
Example 3:
Input: matrix = [[1]] Output: [[1]]
Example 4:
Input: matrix = [[1,2],[3,4]] Output: [[3,1],[4,2]]
Constraints:
• • • •
matrix.length == n
matrix[i].length == n
1 <= n <= 20
-1000 <= matrix[i][j] <= 1000
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5) |
Spiral Matrix – https://leetcode.com/problems/spiral-matrix/ |
Given an
, return all elements of the
in spiral order.
Example 1:
m x n matrix matrix
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [1,2,3,6,9,8,7,4,5]
Example 2:
Input: matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]] Output: [1,2,3,4,8,12,11,10,9,5,6,7]
Constraints:
• • • •
m == matrix.length
n == matrix[i].length
1 <= m, n <= 10
-100 <= matrix[i][j] <= 100
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6) |
Isomorphic Strings |
– https://leetcode.com/problems/isomorphic-strings/ |
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Given two strings s and t, determine if they are isomorphic. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character, but a character may map to itself. Example 1: |
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Input: s = “egg”, t = “add” Output: true |
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Example 2: |
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Input: s = “foo”, t = “bar” Output: false |
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Example 3: |
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Input: s = “paper”, t = “title” Output: true |
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Constraints: |
•
•
• s and t consist of any valid ascii character.
1 <= s.length <= 5 * 104
t.length == s.length
7) Add Strings – https://leetcode.com/problems/add-strings/
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Given two non-negative integers, num1 and num2 represented as string, return the sum of num1 and num2 as a string. You must solve the problem without using any built-in library for handling large integers (such as BigInteger). You must also not convert the inputs to integers directly. Example 1: |
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Input: num1 = “11”, num2 = “123” Output: “134” |
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Example 2: |
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Input: num1 = “456”, num2 = “77” Output: “533” |
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Example 3: |
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Input: num1 = “0”, num2 = “0” Output: “0” |
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Constraints: |
•
- num1 and num2 consist of only digits.
- num1 and num2 don’t have any leading zeros except for the zero itself.
1 <= num1.length, num2.length <= 104
8) Valid Palindrome – https://leetcode.com/problems/valid-palindrome/
Given a string s, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
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Example 1: |
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Input: s = “A man, a plan, a canal: Panama” |
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Example 2: |
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Input: s = “race a car” Output: false |
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Explanation: “raceacar” is not a palindrome. |
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Constraints: |
•
• s consists only of printable ASCII characters.
1 <= s.length <= 2 * 105
9) Reverse words in a String – https://leetcode.com/problems/reverse-words-in-a-string/
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Given an input string s, reverse the order of the words. least one space. Return a string of the words in reverse order concatenated by a single space. Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces. Example 1: |
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Input: s = “the sky is blue” Output: “blue is sky the” |
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Example 2: |
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Input: s = ” hello world ” |
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Example 3: |
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Input: s = “a good example” Output: “example good a” Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string. |
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Example 4: |
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Input: s = ” Bob Loves Alice ” |
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Output: “Alice Loves Bob” |
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Example 5: |
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Input: s = “Alice does not even like bob” Output: “bob like even not does Alice” |
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Constraints: |
•
- s contains English letters (upper-case and lower-case), digits, and spaces ‘ ‘.
- There is at least one word in s.
1 <= s.length <= 104
10) String Compression – https://leetcode.com/problems/string-compression/
Given an array of characters chars, compress it using the following algorithm:
Begin with an empty string s. For each group of consecutive repeating characters in chars:
- If the group’s length is 1, append the character to s.
- Otherwise, append the character followed by the group’s length.
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The compressed string s should not be returned separately, but instead, be stored in the input |
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character array chars. Note that group lengths that are 10 or longer will be split into multiple characters in chars. After you are done modifying the input array, return the new length of the array. |
You must write an algorithm that uses only constant extra space.
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Example 1: |
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Input: chars = [“a”,”a”,”b”,”b”,”c”,”c”,”c”] |
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Output: Return 6, and the first 6 characters of the input array should be: [“a”,”2″,”b”,”2″,”c”,”3″] Explanation: The groups are “aa”, “bb”, and “ccc”. This compresses to “a2b2c3”. |
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Example 2: |
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Input: chars = [“a”] Explanation: The only group is “a”, which remains uncompressed since it’s a single character. |
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Example 3: |
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Input: chars = [“a”,”b”,”b”,”b”,”b”,”b”,”b”,”b”,”b”,”b”,”b”,”b”,”b”] Output: Return 4, and the first 4 characters of the input array should be: [“a”,”b”,”1″,”2″]. |
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Example 4: |
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Input: chars = [“a”,”a”,”a”,”b”,”b”,”a”,”a”] ["a","3","b","2","a","2"]. Explanation: The groups are “aaa”, “bb”, and “aa”. This compresses to “a3b2a2”. Note that each group is independent even if two groups have the same character. |
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Constraints: |
• •
1 <= chars.length <= 2000
is a lowercase English letter, uppercase English letter, digit, or symbol.
chars[i]
