Strings Questions

Author: piyush-eon

#2 - Arrays/#0 - array-basics.js renamed to #2 - Arrays/0-array-basics.js

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+// Strings in Javascript
+
+// Creating Strings
+const string = new String("Subscribe to RoadsideCoder!");
+
+// using double quotes
+const doubleQuote = "Subscribe to RoadsideCoder!"; 
+
+// using single quotes
+const singleQuote = 'RoadsideCoder!'; 
+
+// using backticks
+const backticks = `
+Subscribe to RoadsideCoder! 
+Like this Video
+Share this video
+`;
+
+// Template Literals
+const templateLiteral = `Subscribe to ${singleQuote}!`;
+
+// Tagged Literals
+console.log`hello ${"world"} how are ${"you"}`
+
+// Tagged Literals Example function 
+function test (string, youtubeChannel, person) {
+		console.log(string,youtubeChannel, person)
+    return;
+}
+
+const channel = "RoadsideCoder"
+const name = "Piyush"
+test`Subscribe to ${channel} run by ${name}`
+
+// Strings length
+const str = "Subscribe to RoadsideCoder!";
+str.length
+
+// Accessing Characters
+str[3]
+str.charAt(3)
+ 
+// Looping
+for (let i = 0; i < str.length; i++) {
+    // console.log(str[i]);  
+}
+
+// Modifying Strings
+str[3] = "b" // can't do this
+str.replace("s","b") // replaces first instance of that character or word
+str.replaceAll("e","c")// replaces all instance of that character or word
+
+str.concat(" and share this video") // joins 2 strings
+const newStr = "    Hello  World    "
+newStr.trim() // removes spaces from beginning and end
+
+// Searching
+str.indexOf("Coder") // index of a character or word's first appearance
+
+str.lastIndexOf("e") // index of a character or word's last appearance
+str.indexOf("e") // index of first appearance of "e"
+
+str.startsWith("S")
+str.endsWith("!")
+
+// Extracting Substrings
+str.substring(13, 26)
+str.slice(-14, -1) 
+
+// Converting Case
+const toBeConverted = {name:"Piyush"}
+String(toBeConverted) // [object Object]
+JSON.stringify(toBeConverted) // '{"name":"Piyush"}'
+
+str.toUpperCase() // converts to uppercase
+str.toLowerCase() // converts to lowercase
+
+str.charCodeAt(0) // returns ASCII Code
+String.fromCharCode(65) // returns character from ASCII Code
+
+// String Comparison
+const str1 = "apple"
+const str2 = "apple"
+
+str1.localeCompare(str2) // compare strings
+
+str.includes("Subscribe") // checks if a word exists inside a string
+
+// Splitting and Joining Strings
+str.split("e")
+
+const arr = ["apple", "banana"]
+arr.join(" and ")

#2 - Arrays/#1 - max-and-second-max.js renamed to #2 - Arrays/1-max-and-second-max.js

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+// Ques 1 : Truncate the text
+// Write a function called truncate that checks the length of a given string - str, and if
+// it surpasses a specified maximum length, maxlength, it replaces the end of the string
+// with the ellipsis character "..." so that the length matches the maximum length
+
+// Input: str = "Subscribe to RoadsideCoder" , maxlength=9
+// Output: "Subscribe…"
+
+function truncate(str,maxlength) {
+    if (str.length > maxlength)
+        return str.slice(0, maxlength) + "..."
+    else return str
+}
+
+console.log(truncate("Subscribe to RoadsideCoder", 9));

#2 - Arrays/#2 - rotate-arrays-by-k.js renamed to #2 - Arrays/2-rotate-arrays-by-k.js

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+// Ques 2 - Palindrome Number
+// An integer is a palindrome when it reads the same forward and backward.
+
+// Input: x = 121  ----->>>>>   Output: true
+// Input: x = 10   ----->>>>>   Output: false
+
+var isPalindrome = function (x) {
+  return x < 0 ? false : x === +x.toString().split("").reverse().join("");
+};
+
+const res = isPalindrome(10);
+console.log(res);
+
+// 121 => "121" => ["1","2","1"] => ["1","2","1"] => "121"

#2 - Arrays/#3 - remove-duplicates.js renamed to #2 - Arrays/3-remove-duplicates.js

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+// Ques 3 : Hamming Distance
+// Given two strings x and y, return the Hamming distance between them.
+
+// Input: x = "hello", y = "hwllr"
+// Output: 2
+// Explanation:
+//   (hello)
+//   (hwllr)
+//     ↑  ↑
+
+function hammingDistance(x,y) {
+    if (x.length !== y.length) {
+        throw new Error("Strings must be of same length")
+    }
+
+    let distance = 0;
+
+    for (let i = 0; i < x.length; i++){
+        if (x[i] !== y[i]) {
+            distance++
+        }
+    }
+
+    return distance
+}
+
+console.log(hammingDistance("hello","hwllr"));
+
+// Variation 2: Given two integers x and y, return the Hamming distance between thier bits.
+
+// Input: x = 1, y = 4
+// Output: 2
+// Explanation:
+// 1   (0 0 0 1)
+// 4   (0 1 0 0)
+//        ↑   ↑
+
+function hammingDistance(x, y) {
+    x=x.toString(2)
+    y=y.toString(2)
+
+    if (x.length < y.length) {
+        while(x.length!==y.length) x="0"+x
+    } else {
+         while(x.length!==y.length) y="0"+y
+    }
+
+    let distance = 0;
+
+    for (let i = 0; i < x.length; i++){
+        if (x[i] !== y[i]) {
+            distance++
+        }
+    }
+
+    return distance
+}
+
+console.log(hammingDistance(2,9));

#2 - Arrays/#4 - maximum-sum-subarray.js renamed to #2 - Arrays/4-maximum-sum-subarray.js

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+// Ques 4 - Valid Anagram
+// An Anagram is a word or phrase formed by rearranging the letters of
+// a different word or phrase, using all the original letters exactly once.
+
+// Input: (s = "anagram"), (t = "nagaram"); ----->>>>>   Output: true;
+// Input: (s = "rat"), (t = "car");         ----->>>>>   Output: false;
+
+// 1st Approach
+const isAnagram1 = function (s, t) {
+  s = s.split("").sort().join("");
+  t = t.split("").sort().join("");
+
+  return s === t;
+};
+
+// anagram => [a,n,a,g,r,a,m] => [a,a,a,m,n,r] => aaamnr
+// nagaram => [n,a,g,a,r,a,m] => [a,a,a,m,n,r] => aaamnr
+
+const isAnagram = function (s, t) {
+  if (s.length !== t.length) return false;
+
+  let obj1 = {};
+  let obj2 = {};
+
+  for (let i = 0; i < s.length; i++) {
+    obj1[s[i]] = (obj1[s[i]] || 0) + 1;
+    obj2[t[i]] = (obj2[t[i]] || 0) + 1;
+  }
+
+  for (const key in obj1) {
+    if (obj1[key] !== obj2[key]) return false;
+  }
+
+  return true;
+};
+
+console.log(isAnagram("anagram", "nagarm"));
+
+// rat / tar
+
+// {
+//     r: 1,
+//     a: 1,
+//     t:1
+// }
+
+// {
+//     t: 1,
+//     a: 1,
+//     r:1
+// }