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Suppose we have an array A. We have to rotate right it k steps. So if the array is A = [5, 7, 3, 6, 8, 1, 5, 4], and k = 3, then the output will be [1, 5, 4, 5, 7, 3, 6, 8]. The steps are like[4, 5, 7, 3, 6, 8, 1, 5][5, 4, 5, 7, 3, 6, 8, 1][1, 5, 4, 5, 7, 3, 6, 8]To solve this, we will follow these steps.let n is the size of the arrayk = k mod nA = subarray of A from n – k to end + ... Read More
Here we will see how to calculate the number of trailing 0s for the result of factorial of any number. So if the n = 5, then 5! = 120. There is only one trailing 0. For 20! it will be 4 zeros as 20! = 2432902008176640000.The easiest approach is just calculating the factorial and count the 0s. But this approach fails for a large value of n. So we will follow another approach. The trailing zeros will be there if the prime factors are 2 and 5. If we count the 2s and 5s we can get the result. ... Read More
We know that the excel column numbers are alphabetic. It starts from A, and after Z, it will AA, AB, to ZZ, then again AAA, AAB, to ZZZ and so on. So column 1 is A, column 27 is Z. Here we will see how to get the column letter if a number of columns is given. So if the column number is 80, then it will be CB.Suppose we have a number n, and its value is 28, then we need to take a reminder with 26. If the remainder is 0, then the number is 26, 52 and ... Read More
Suppose we have an array; we have to check whether given number x is the majority element of that array or not. The array is sorted. One element is said to be the majority element when it appears n/2 times in the array. Suppose an array is like {1, 2, 3, 3, 3, 3, 6}, x = 3, here the answer is true as 3 is the majority element of the array. There are four 3s. The size of the array is 7, so we can see 4 > 7/2.We can count the occurrences of x in the array, and ... Read More
Suppose we have an array A. In this array there are many numbers that occur twice. Only one element can be found a single time. We have to find that element from that array. Suppose A = [1, 1, 5, 3, 2, 5, 2], then the output will be 3. As there is each number twice, we can perform XOR to cancel out that element. because we know y XOR y = 0To solve this, we will follow these steps.Take one variable res = 0for each element e in array A, preform res = res XOR ereturn resExampleLet us see ... Read More
Suppose we have a string with alphanumeric values and symbols. There are lower case and uppercase letters as well. We have to check whether the string is forming a palindrome or not by considering only the lowercase letters (uppercases will be converted into lower case), other symbols like a comma, space will be ignored.Suppose the string is like “A Man, a Plan, a Canal: Panama”, then by considering these rules, it will be “amanaplanacanalpanama”. This is a palindrome.To solve this, follow these steps −define x = “”read each character c in str −if c is lowercase letter or number, then ... Read More
Suppose we have an array A, here A[i] is indicating the price of a given stock on day i. We have to find the maximum profit. We can complete as many transactions as we like. (Transaction means to buy and sell stocks). But we have to keep in mind that we may not engage in multiple transactions at the same time. So we have to sell the stock before buying the new one.Suppose the array is like A = [7, 1, 5, 3, 6, 4], then the result will be 7. As we can see, if we buy on day ... Read More
Suppose we have an array A, here A[i] is indicating the price of a given stock on day i. We have to find the maximum profit. We can complete at most one transaction. (Transaction means to buy and sell stocks). But we have to keep in mind that we may not engage in multiple transactions at the same time. So we have to sell the stock before buying the new one.Suppose the array is like A = [7, 1, 5, 3, 6, 4], then the result will be 5. As we can see, if we buy on day 2 (index ... Read More
Suppose a decimal number can be converted to its Hexspeak representation by converting it to an uppercase hexadecimal string at first, after that replacing all occurrences of the digit 0 with the letter O, and the digit 1 with the letter I.This kind of representation is valid if and only if it consists only of the letters in the set {"A", "B", "C", "D", "E", "F", "I", "O"}.So we have a string num representing a decimal integer N, we have to find the Hexspeak representation of N if it is correct, otherwise return "ERROR". So if num = “257”, then ... Read More
Suppose we have one tree and a sum. We have to find one path such that if we follow that path, we will get the sum that will be matched with the given sum. Suppose the tree is like [0, -3, 9, -10, null, 5] and the sum is 14, then there is a path 0 → 9 → 5To solve this, we will follow these steps.If the root is null, then return Falseif left and right subtree are empty, then return true when sum – root.val = 0, otherwise falsereturn solve(root.left, sum – root.val) or solve(root.right, sum – root.val)Let ... Read More