Coding Solutions

Question You have n boxes. You are given a binary string boxes of length n, where boxes[i] is '0' if the ith box is empty, and '1' if it contains one ball. In one operation, you can move one ball from a box to an adjacent box. Box i is adjacent to box j if abs(i - j) == 1. Note that after doing so, there may be more than one ball in some boxes. Return an array answer of size n, where answer[i] is the minimum number of operations needed to move all the balls to the ith box. Each answer[i] is calculated considering the initial state of the boxes. Example 1: Input: boxes = "110" Output: [1,1,3] Explanation: The answer for each box is as follows: 1) First box: you will have to move one ball from the second box to the first box in one operation. 2) Second box: you will have to move one ball from the first box to the second box in one operation. 3) Third box: you will have to move one ball from the first box to the third box in two operations, and move one ball fr...

Question Given the root of an n-ary tree, return the postorder traversal of its nodes' values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples) Example 1: Input: root = [1,null,3,2,4,null,5,6] Output: [5,6,3,2,4,1] Example 2: Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14] Output: [2,6,14,11,7,3,12,8,4,13,9,10,5,1] Solution class Solution { public: vector v; vector postorder(Node* root) { if(root==NULL) return v; for(int i=0;i children.size();i++){ postorder(root->children[i]); } v.push_back(root->val); return v; } };

Question Given a 0-indexed string word and a character ch, reverse the segment of word that starts at index 0 and ends at the index of the first occurrence of ch (inclusive). If the character ch does not exist in word, do nothing. For example, if word = "abcdefd" and ch = "d", then you should reverse the segment that starts at 0 and ends at 3 (inclusive). The resulting string will be "dcbaefd". Return the resulting string. Example 1: Input: word = "abcdefd", ch = "d" Output: "dcbaefd" Explanation: The first occurrence of "d" is at index 3. Reverse the part of word from 0 to 3 (inclusive), the resulting string is "dcbaefd". Example 2: Input: word = "xyxzxe", ch = "z" Output: "zxyxxe" Explanation: The first and only occurrence of "z" is at index 3. Reverse the part of word from 0 to 3 (inclusive), the resulting string is "zxyxxe". Solution class Solution ...

Question You are given a 0-indexed integer array nums and a target element target. A target index is an index i such that nums[i] == target. Return a list of the target indices of nums after sorting nums in non-decreasing order. If there are no target indices, return an empty list. The returned list must be sorted in increasing order. Example 1: Input: nums = [1,2,5,2,3], target = 2 Output: [1,2] Explanation: After sorting, nums is [1,2,2,3,5]. The indices where nums[i] == 2 are 1 and 2. Example 2: Input: nums = [1,2,5,2,3], target = 3 Output: [3] Explanation: After sorting, nums is [1,2,2,3,5]. The index where nums[i] == 3 is 3. Solution class Solution { public: vector targetIndices(vector & nums, int target) { vector v; sort(nums.begin(),nums.end()); for(int i=0;i

Question Given a sorted integer array arr, two integers k and x, return the k closest integers to x in the array. The result should also be sorted in ascending order. An integer a is closer to x than an integer b if: |a - x| findClosestElements(vector & arr, int k, int x) { vector result; for(auto itr=arr.begin();itr!=arr.end();itr++) *itr-=x; sort(arr.begin(),arr.end(),[](int a, int b){return (a==-1*b && a

Question You are given an m x n binary matrix mat of 1's (representing soldiers) and 0's (representing civilians). The soldiers are positioned in front of the civilians. That is, all the 1's will appear to the left of all the 0's in each row. A row i is weaker than a row j if one of the following is true: The number of soldiers in row i is less than the number of soldiers in row j. Both rows have the same number of soldiers and i kWeakestRows(vector >& mat, int k) { vector v; map m; int x=0; for(int i=0;i m[j]){ min = m[j]; d=j; } } v.push_back(d); m[d]=INT_MAX; } return v; } };

Question Given a callable function f(x, y) with a hidden formula and a value z, reverse engineer the formula and return all positive integer pairs x and y where f(x,y) == z. You may return the pairs in any order. While the exact formula is hidden, the function is monotonically increasing, i.e.: f(x, y) f(1, 4) = 1 + 4 = 5. x=2, y=3 -> f(2, 3) = 2 + 3 = 5. x=3, y=2 -> f(3, 2) = 3 + 2 = 5. x=4, y=1 -> f(4, 1) = 4 + 1 = 5. Example 2: Input: function_id = 2, z = 5 Output: [[1,5],[5,1]] Explanation: The hidden formula for function_id = 2 is f(x, y) = x * y. The following positive integer values of x and y make f(x, y) equal to 5: x=1, y=5 -> f(1, 5) = 1 * 5 = 5. x=5, y=1 -> f(5, 1) = 5 * 1 = 5. Solution class Solution { public: vector > findSolution(CustomFunction& customfunction, int z) { vector > ans; int j = 1000; for(int i=1; i 1 && customfunction.f(i, j) > z) j--; if(customfunction.f(i, j) == z) ans.push...

Quesition Given two integer arrays arr1 and arr2, and the integer d, return the distance value between the two arrays. The distance value is defined as the number of elements arr1[i] such that there is not any element arr2[j] where |arr1[i]-arr2[j]| d=2 |4-9|=5 > d=2 |4-1|=3 > d=2 |4-8|=4 > d=2 For arr1[1]=5 we have: |5-10|=5 > d=2 |5-9|=4 > d=2 |5-1|=4 > d=2 |5-8|=3 > d=2 For arr1[2]=8 we have: |8-10|=2 d=2 |8-8|=0 & arr1, vector & arr2, int d) { int value = 0; int n = arr1.size(), m = arr2.size(); for(int i = 0; i

Question Given a positive integer n, return the smallest positive integer that is a multiple of both 2 and n. Example 1: Input: n = 5 Output: 10 Explanation: The smallest multiple of both 5 and 2 is 10. Example 2: Input: n = 6 Output: 6 Explanation: The smallest multiple of both 6 and 2 is 6. Note that a number is a multiple of itself. Solution class Solution { public: int smallestEvenMultiple(int n) { if(n%2==0) return n; return 2*n; } }; // 100 Faster

Question You're given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels. Letters are case sensitive, so "a" is considered a different type of stone from "A". Example 1: Input: jewels = "aA", stones = "aAAbbbb" Output: 3 Example 2: Input: jewels = "z", stones = "ZZ" Output: 0 Solution class Solution { public: int numJewelsInStones(string jewels, string stones) { int d=0; for(int i=0;i

Question There are n kids with candies. You are given an integer array candies, where each candies[i] represents the number of candies the ith kid has, and an integer extraCandies, denoting the number of extra candies that you have. Return a boolean array result of length n, where result[i] is true if, after giving the ith kid all the extraCandies, they will have the greatest number of candies among all the kids, or false otherwise. Note that multiple kids can have the greatest number of candies. Example 1: Input: candies = [2,3,5,1,3], extraCandies = 3 Output: [true,true,true,false,true] Explanation: If you give all extraCandies to: - Kid 1, they will have 2 + 3 = 5 candies, which is the greatest among the kids. - Kid 2, they will have 3 + 3 = 6 candies, which is the greatest among the kids. - Kid 3, they will have 5 + 3 = 8 candies, which is the greatest among the kids. - Kid 4, they will have 1 + 3 = 4 candies, which is not the greatest among the kids. - Kid 5, they will have 3 ...

Question Implement the class SubrectangleQueries which receives a rows x cols rectangle as a matrix of integers in the constructor and supports two methods: 1. updateSubrectangle(int row1, int col1, int row2, int col2, int newValue) Updates all values with newValue in the subrectangle whose upper left coordinate is (row1,col1) and bottom right coordinate is (row2,col2). 2. getValue(int row, int col) Returns the current value of the coordinate (row,col) from the rectangle. Example 1: Input ["SubrectangleQueries","getValue","updateSubrectangle","getValue","getValue","updateSubrectangle","getValue","getValue"] [[[[1,2,1],[4,3,4],[3,2,1],[1,1,1]]],[0,2],[0,0,3,2,5],[0,2],[3,1],[3,0,3,2,10],[3,1],[0,2]] Output [null,1,null,5,5,null,10,5] Explanation SubrectangleQueries subrectangleQueries = new SubrectangleQueries([[1,2,1],[4,3,4],[3,2,1],[1,1,1]]); // The initial rectangle (4x3) looks like: // 1 2 1 // 4...

Question You own a Goal Parser that can interpret a string command. The command consists of an alphabet of "G", "()" and/or "(al)" in some order. The Goal Parser will interpret "G" as the string "G", "()" as the string "o", and "(al)" as the string "al". The interpreted strings are then concatenated in the original order. Given the string command, return the Goal Parser's interpretation of command. Example 1: Input: command = "G()(al)" Output: "Goal" Explanation: The Goal Parser interprets the command as follows: G -> G () -> o (al) -> al The final concatenated result is "Goal". Example 2: Input: command = "G()()()()(al)" Output: "Gooooal" Example 3: Input: command = "(al)G(al)()()G" Output: "alGalooG" Solution class Solution { public: string check(string x){ if(x=="G") re...

Question Assume you are an awesome parent and want to give your children some cookies. But, you should give each child at most one cookie. Each child i has a greed factor g[i], which is the minimum size of a cookie that the child will be content with; and each cookie j has a size s[j]. If s[j] >= g[i], we can assign the cookie j to the child i, and the child i will be content. Your goal is to maximize the number of your content children and output the maximum number. Example 1: Input: g = [1,2,3], s = [1,1] Output: 1 Explanation: You have 3 children and 2 cookies. The greed factors of 3 children are 1, 2, 3. And even though you have 2 cookies, since their size is both 1, you could only make the child whose greed factor is 1 content. You need to output 1. Example 2: Input: g = [1,2], s = [1,2,3] Output: 2 Explanation: You have 2 children and 3 cookies. The greed factors of 2 children are 1, 2. You have 3 cookies and their sizes are big enough to gratify all of the children,...

Question Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), ..., (an, bn) such that the sum of min(ai, bi) for all i is maximized. Return the maximized sum. Example 1: Input: nums = [1,4,3,2] Output: 4 Explanation: All possible pairings (ignoring the ordering of elements) are: 1. (1, 4), (2, 3) -> min(1, 4) + min(2, 3) = 1 + 2 = 3 2. (1, 3), (2, 4) -> min(1, 3) + min(2, 4) = 1 + 2 = 3 3. (1, 2), (3, 4) -> min(1, 2) + min(3, 4) = 1 + 3 = 4 So the maximum possible sum is 4. Example 2: Input: nums = [6,2,6,5,1,2] Output: 9 Explanation: The optimal pairing is (2, 1), (2, 5), (6, 6). min(2, 1) + min(2, 5) + min(6, 6) = 1 + 2 + 6 = 9. Solution class Solution { public: int arrayPairSum(vector & nums) { sort(nums.begin(),nums.end()); int d=0; for(int i=0;i

Question Given the array nums, for each nums[i] find out how many numbers in the array are smaller than it. That is, for each nums[i] you have to count the number of valid j's such that j != i and nums[j] smallerNumbersThanCurrent(vector & nums) { vector v; for(int i=0;i nums[j]) x++; } v.push_back(x); } return v; } };

Question A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each word consists of lowercase and uppercase English letters. A sentence can be shuffled by appending the 1-indexed word position to each word then rearranging the words in the sentence. For example, the sentence "This is a sentence" can be shuffled as "sentence4 a3 is2 This1" or "is2 sentence4 This1 a3". Given a shuffled sentence s containing no more than 9 words, reconstruct and return the original sentence. Example 1: Input: s = "is2 sentence4 This1 a3" Output: "This is a sentence" Explanation: Sort the words in s to their original positions "This1 is2 a3 sentence4", then remove the numbers. Example 2: Input: s = "Myself2 Me1 I4 and3" Output: "Me Myself and I" Explanation: Sort the words in s to their original positions "Me1 Myself2 and3 I4", then remove the numbers. Soluti...

Question An integer n is strictly palindromic if, for every base b between 2 and n - 2 (inclusive), the string representation of the integer n in base b is palindromic. Given an integer n, return true if n is strictly palindromic and false otherwise. A string is palindromic if it reads the same forward and backward. Example 1: Input: n = 9 Output: false Explanation: In base 2: 9 = 1001 (base 2), which is palindromic. In base 3: 9 = 100 (base 3), which is not palindromic. Therefore, 9 is not strictly palindromic so we return false. Note that in bases 4, 5, 6, and 7, n = 9 is also not palindromic. Example 2: Input: n = 4 Output: false Explanation: We only consider base 2: 4 = 100 (base 2), which is not palindromic. Therefore, we return false. Solution class Solution { public: bool pal(string d){ for(int i=0;i

Question You are given a 0-indexed integer array nums and an integer pivot. Rearrange nums such that the following conditions are satisfied: Every element less than pivot appears before every element greater than pivot. Every element equal to pivot appears in between the elements less than and greater than pivot. The relative order of the elements less than pivot and the elements greater than pivot is maintained. More formally, consider every pi, pj where pi is the new position of the ith element and pj is the new position of the jth element. For elements less than pivot, if i pivot and nums[j] > pivot, then pi pivotArray(vector & nums, int pivot) { vector s; vector l; int d=0; for(int i=0;i

Question Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Example 1: Input: s = "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc" Example 2: Input: s = "God Ding" Output: "doG gniD" Solution class Solution { public: string rev(string s){ string x=""; for(int i=0;i