Suppose we have a string s of lowercase alphabet characters, other characters like "[", "|", and "]". Here "[a|b|c]" indicates either "a", "b", or "c" can be chosen as a possibility. We have to find a list of strings containing all possible values that s can represent. Here "[]" cannot be nested and may have any number of choices.So, if the input is like s = "[d|t|l]im[e|s]", then the output will be ['dime', 'dims', 'lime', 'lims', 'time', 'tims']To solve this, we will follow these steps:if s is empty, thenreturn a list with blank stringn := size of sseq := a ... Read More

Suppose we have a list of numbers called nums and another value k. Now let us consider an operation where we can subtract 1 from any element in the list. We can perform this operation k times. We have to find the minimum possible maximum value in the list after k such operations.So, if the input is like nums = [3, 4, 6, 5] k = 6, then the output will be 3, as we can decrease 4 once, 6 thrice and 5 twice to get [3, 3, 3, 3].To solve this, we will follow these steps:sort numbers in reverse ... Read More

Suppose we have a binary tree; we have to find the number of nodes that are an only child. As we know a node x is called an only child node when its parent has exactly one child that is x.So, if the input is likethen the output will be 2 as 8 and 6 are the only children.To solve this, we will follow these steps:if root is null, thenreturn 0d := a double ended queueinsert root at the end of dcount := 0while d is not empty, docurrent := left element of d and delete left elementif left of ... Read More

Suppose we have a list of distinct numbers; we have to find the minimum number of swaps required to sort the list in increasing order.So, if the input is like nums = [3, 1, 7, 5], then the output will be 2, as we can swap 3 and 1, then 5 and 7.To solve this, we will follow these steps:sort_seq := sort the list numstable := a new mapfor each index i and value n in nums, dotable[n] := iswaps := 0for i in range 0 to size of nums, don := nums[i]s_n := sort_seq[i]s_i := table[s_n]if s_n is not ... Read More

Suppose we have a list of numbers called nums and another value target, we have to find the number of sublists whose sum is same as target.So, if the input is like nums = [3, 0, 3] target = 3, then the output will be 4, as we have these sublists whose sum is 3: [3], [3, 0], [0, 3], [3].To solve this, we will follow these steps:temp := an empty maptemp[0] := 1s := 0ans := 0for i in range 0 to size of nums, dos := s + nums[i]comp := s - targetif comp is in temp, thenans ... Read More

Suppose we have a list nums, and two additional values k and target, we have to find the number of sublists whose size is k and its average value ≥ target.So, if the input is like nums = [1, 10, 5, 6, 7] k = 3 target = 6, then the output will be 2, as the sublist [1, 10, 7] has average value of 6 and [10, 5, 6] has average of 7.To solve this, we will follow these steps:target := target * ksum := 0, ans := 0for each index i and number n in nums, doif i ... Read More

Suppose we have a list of fractions where each fraction is individual lists [numerator, denominator] which represents the number (numerator / denominator). We have to find the number of pairs of fractions whose sum is 1.So, if the input is like fractions = [[2, 7], [3, 12], [4, 14], [5, 7], [3, 4], [1, 4]], then the output will be 4, as (2/7 + 5/7), (3/12 + 3/4), (3/4 + 1/4), (4/14 + 5/7) are the four pairs which sum to 1.To solve this, we will follow these steps:d := a new mapans := 0for each fraction i in fractions, ... Read More

Suppose we have a number n, we have to find the largest number smaller or equal to n where all digits are non-decreasing.So, if the input is like n = 221, then the output will be 199.To solve this, we will follow these steps:digits := a list with all digits in nbound := nullfor i in range size of digits - 1 down to 0, doif digits[i] < digits[i - 1], thenbound := idigits[i - 1] := digits[i - 1] - 1if bound is not null, thenfor i in range bound to size of digits, dodigits[i] := 9join each digit ... Read More

Suppose we have a number n and another value k. Now let us consider a string containing only "0", "1", and "2"s where no character is repeated in succession. We have to select such strings of length n and find the kth lexicographically smallest string. If there is no kth string, return empty string.So, if the input is like n = 4 k = 2, then the output will be "0120".To solve this, we will follow these steps:define a method solve() this will take s, k and lastif s is same as 0, thenreturn blank stringfor each character c in ... Read More

Suppose we have a number n, we have to find first n numbers that are sorted in lexicographic sequence.So, if the input is like n = 15, then the output will be [1, 10, 11, 12, 13, 14, 15, 2, 3, 4, 5, 6, 7, 8, 9]To solve this, we will follow these steps:count := 1ans := a list with single element countwhile size of ans < n, docount := count * 10while count > n , docount := quotient of count / 10count := count + 1while count mod 10 is same as 0, docount := quotient of count ... Read More