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Suppose we have a binary tree containing values 0, 1 and 2. The root has at least one 0 node and one 1 node. Now suppose there is an operation where we delete an edge in the tree and the tree becomes two different trees. We have to find the number of ways we can delete one edge such that none of the two trees contain both a 0 node and a 1 node.So, if the input is likethen the output will be 1 as we can only delete the 0 to 2 edge.To solve this, we will follow these ... Read More
Suppose we have a binary tree, we have to find a list of two numbers where the first number is the count of leaves in the tree and the second number is the count of non-leaf nodes.So, if the input is likethen the output will be (3, 2), as there are 3 leaves and 2 non-leaf nodes.To solve this, we will follow these steps −if n is null, thenreturn (0, 0)if left of n is null and right of n is null, thenreturn (1, 0)left := solve(left of n)right := solve(right of n)return (left[0] + right[0], 1 + left[1] + ... Read More
Suppose we have a binary tree where each node contains a digit from 0-9, we have to check whether its in-order traversal is palindrome or not.So, if the input is likethen the output will be True, as its inorder traversal is [2, 6, 10, 6, 2].To solve this, we will follow these steps −if root is null, thenreturn Truestack := a new stackcurr := rootinorder := a new listwhile stack is not empty or curr is not null, dowhile curr is not null, dopush curr into stackcurr := left of currnode := popped element from stackinsert value of node at ... Read More
Suppose we have a string s, we have to check whether any permutation of s is a palindrome or not.So, if the input is like s = "admma", then the output will be True, as we can rearrange "admma" to "madam" which is a palindrome.To solve this, we will follow these steps −c := a map holding each individual character count of scount := 0for each i in list of all values of c, doif i is odd, thenif count is same as 0, thencount := count + 1come out from the loopreturn Falsereturn TrueLet us see the following implementation ... Read More
Suppose we have a linked list. We have to check whether the list elements are forming a palindrome or not. So if the list element is like [5, 4, 3, 4, 5], then this is a palindrome, but a list like [5, 4, 3, 2, 1] is not a palindrome.To solve this, we will follow these steps −fast := head, slow := head, rev := None and flag := 1if head is empty, then return truewhile fast and next of fast is availableif next of the next of fast is available, then set flag := 0 and break the loopfast ... Read More
Suppose we have a linked list. We have to swap every two adjacent nodes (pair) and return its head. Here the constraint is that, we cannot modify the value of the nodes, only the node itself can be changed. So if the list is like [1, 2, 3, 4], then the resultant list will be [2, 1, 4, 3].To solve this, we will follow these steps −if head is not present, then return headfirst := head, second := next of head, dummy is one new node with value -1next of dummy := first, and prev := dummywhile second is not ... Read More
Suppose we have a list of numbers called nums and another value target. We have to find the maximum number of pairs where for each pair i < j, i and j are not in any other pair, and |nums[i] - nums[j]| >= target.So, if the input is like nums = [2, 4, 6, 10, 11], target = 5, then the output will be 2, as we can get pairs: (2, 6), (5, 10)To solve this, we will follow these steps −N := size of Asort the list Aans := 0j := N / 2for i in range 0 to ... Read More
Suppose we have a 2D grid, containing colors as strings "r", "g", and "b". We have to perform floodfill operation at row r, column c with the color target. As we know the Floodfill operation should replace all elements that are both connected to grid[r, c] (up/right/down/left) and have the same color as grid[r, c] with the same color as target.So, if the input is likeRRRRGBGBBthen the output will beGGGGGBGBBas the red cells connected to grid[0, 0] are replaced with green ("g").To solve this, we will follow these steps −define a new set seenoldcolor := matrix[r, c]Define a function dfs() ... Read More
Suppose we have a list of numbers nums, we will pack consecutive elements of the same value into sublists. We have to keep in mind that there is only one occurrence in the list it should still be in its own sublist.So, if the input is like nums = [5, 5, 2, 7, 7, 7, 2, 2, 2, 2], then the output will be [[5, 5], [2], [7, 7, 7], [2, 2, 2, 2]]To solve this, we will follow these steps −if nums is empty, thenreturn a new listresult := a list with another list that contains nums[0]j := 0for ... Read More
Suppose we have a 2D list of numbers called intervals where each row represents [start, end] (inclusive) interval. For an interval [a, b] (a < b), its size is (b - a). We must add one interval to the given list such that, after merging all the intervals, we get exactly one range left. We have to find the minimum possible size of the added interval.So, if the input is like intervals = [[15, 20], [30, 50]], then the output will be 10, as we can add the interval [20, 30] which is the smallest possible interval.To solve this, we ... Read More