dluciano

public class Solution {
  public IList<string> TopKFrequent(string[] words, int k) {
    var freq = words.Freq();
    var sortedList = new SortedList<int, SortedSet<string>>();
    
    foreach(var kv in freq){
      var key = -kv.Value;      
      if(!sortedList.ContainsKey(key))
        sortedList.Add(key, new());
      sortedList[key].Add(kv.Key);

dluciano

public class Solution {
  public TreeNode AddOneRow(TreeNode root, int val, int depth) {
    if(depth == 1){
      var tempLeft = root;
      root = new TreeNode(val);
      root.left = tempLeft;
      return root;
    }

    var queue = new Queue<TreeNode>();

dluciano

public class Solution {
  private int acc;
  public bool HasPathSum(TreeNode root, int targetSum) {
    if(root is null)
      return false;
    acc +=  root.val;
    if(root.left is null && root.right is null && acc == targetSum)
      return true;
    if(HasPathSum(root.left, targetSum))
      return true;

dluciano

public class Solution {
  public int MinCost(string colors, int[] neededTime) {
    var min = 0;
    (int, PriorityQueue<int, int>?) GetEqualColourBallons(int index){
      var pq = new PriorityQueue<int, int>();
      if(index + 1 >= colors.Length || colors[index] != colors[index + 1])
        return (index + 1, null);
      var colour = colors[index];
      while(index < colors.Length && colors[index] == colour){
        pq.Enqueue(neededTime[index], neededTime[index]);

dluciano

public class Solution {
  private const long MOD = 1000000007;
  public int NumRollsToTarget(int dices, int faces, int target) {
    var dp = new long[dices + 1, target + 1];
    dp[0,0] = 1;
    for(var dice = 1; dice <= dices; ++dice){
      for(var acc = 0; acc <= target; ++acc){
        for(var face = 1; face <= faces; ++face){
          if(acc < face) 
            break;

dluciano

public class Solution {
  public int FindLonelyPixel(char[][] picture) {
    var ROWS = picture.Length;
    var COLS = picture[0].Length;
    var lonelyColumns = new BitArray(COLS);

    for(var col = 0; col < COLS; ++col){
      var lonelyCounter = 0;
      for(var row = 0; row < ROWS; ++row){
        if(picture[row][col] == 'B')

dluciano

public class Solution {
  public int NumDecodings(string s) {
    var memo = new int?[s.Length];
    int Counter(in int index = 0){
      if(index >= s.Length)
        return 1;
            
      if(s[index] == '0')
        return 0;
      

dluciano

public class Solution {
  public IList<int> KillProcess(IList<int> pid, IList<int> ppid, int kill) {
    var adj = new Dictionary<int, List<int>>();
    for(var i = 0; i < pid.Count; i++){
      if(!adj.ContainsKey(pid[i]))
        adj[pid[i]] = new();
      if(!adj.ContainsKey(ppid[i]))
        adj[ppid[i]] = new();
      
      adj[ppid[i]].Add(pid[i]);

dluciano

public class Solution {
  public IList<IList<int>> GetSkyline(int[][] buildings) {
    var result = new List<IList<int>>();
    var buildingSortedByHeights = buildings.OrderByDescending(b => b[2]).ToArray();
    
    var x1s = buildings.Select(b => b[0]).ToArray();
    var x2s = buildings.Select(b => b[1]).ToArray();
    var xs = x1s.Concat(x2s).Distinct().OrderBy(x => x).ToArray();
    
    var curHeight = int.MinValue;

dluciano

public class Solution {    
    public ListNode RemoveNthFromEnd(ListNode head, int n) {
        ListNode slow = head, fast = head;
        for(var i = 0; i < n; i++) 
          fast = fast.next;
        if(fast == null) 
          return head.next;
        while(fast.next != null)
          (fast, slow) = (fast.next, slow.next);