public static void fnTopKFrequentNumbers()
{
int[] nums = new int[] { 6, 0, 1, 4, 9, 7, -3, 1, -4, -8, 4, -7, -3, 3, 2, -3, 9, 5, -4, 0 };
int k = 6;
IList <int> list = new List <int>();
if (nums == null || nums.Length == 0)
{
return;
}
Dictionary <int, int> dict = new Dictionary <int, int>();
for (int i = 0; i < nums.Length; i++)
{
if (!dict.ContainsKey(nums[i]))
{
dict.Add(nums[i], 0);
}
dict[nums[i]]++;
}
MinHeapRecurse <NumToCount> minHeap = new MinHeapRecurse <NumToCount>(k, new NumToCountComparer());
foreach (var item in dict)
{
NumToCount nc = new NumToCount(item.Key, item.Value);
if (minHeap.Size() == k)
{
if (minHeap.Peek().count < nc.count)
{
minHeap.DeleteMin();
}
}
minHeap.Insert(nc);
}
int l = minHeap.Size();
while (l-- > 0)
{
list.Add(minHeap.DeleteMin().number);
}
list.Reverse();
for (int i = 0; i < list.Count; i++)
{
Console.Write(list[i] + " ");
}
Console.WriteLine();
}
public static void fnTopKFrequentWords()
{
//string[] arr = new string[] { "geek", "i", "love", "leetcode", "i", "love", "coding", "geek" };
//string[] arr = new string[] { "the", "day", "is", "sunny", "the", "the", "the", "sunny", "is", "is", };
string[] arr = new string[] { "i", "love", "leetcode", "i", "love", "coding" };
Dictionary <string, int> dict = new Dictionary <string, int>();
int k = 3;
for (int i = 0; i < arr.Length; i++)
{
if (!dict.ContainsKey(arr[i]))
{
dict.Add(arr[i], 0);
}
dict[arr[i]]++;
}
MinHeapRecurse <StringToCount> minHeap = new MinHeapRecurse <StringToCount>(k, new StringToCountComparer());
foreach (var item in dict)
{
StringToCount sc = new StringToCount(item.Key, item.Value);
if (minHeap.Size() == k)
{
if (minHeap.Peek().count < sc.count ||
(minHeap.Peek().count < sc.count && sc.str.CompareTo(minHeap.Peek().str) < 0))
{
minHeap.DeleteMin();
}
}
minHeap.Insert(sc);
}
List <string> strList = new List <string>();
int l = minHeap.Size();
while (l-- > 0)
{
strList.Add(minHeap.DeleteMin().str);
}
strList.Reverse();
for (int i = 0; i < strList.Count; i++)
{
Console.Write(strList[i] + " ");
}
Console.WriteLine();
}
public static string fnRemoveKdigits(string num, int k)
{
if (string.IsNullOrEmpty(num) || num.Length < k)
{
return(string.Empty);
}
MinHeapRecurse <int> mh = new MinHeapRecurse <int>(k, new IntComparer());
for (int i = 0; i < num.Length; i++)
{
if (k == mh.Size())
{
if ((num[i] - '0') > mh.Peek())
{
mh.DeleteMin();
}
}
mh.Insert(num[i] - '0');
}
HashSet <int> hs = new HashSet <int>();
while (mh.Size() > 0)
{
var del = mh.DeleteMin();
hs.Add(del);
}
StringBuilder sb = new StringBuilder();
for (int j = num.Length - 1; j >= 0; j--)
{
if (!hs.Contains(num[j] - '0'))
{
sb.Append(num[j]);
}
else
{
hs.Remove(num[j] - '0');
}
}
var list = sb.ToString().Reverse().ToArray();
list.Reverse();
return(new string(list));
}
public static void kLargest()
{
int t = 1;
while (t-- > 0)
{
int[] sizeAndLength = new int[] { 8, 3 };
int[] array = Array.ConvertAll("1 23 12 90 100 30 2 50".Split(' '), int.Parse);
MinHeapRecurse <int> minHeap = new MinHeapRecurse <int>(sizeAndLength[1], new IntComparer());
for (int i = 0; i < sizeAndLength[1]; i++)
{
minHeap.Insert(array[i]);
}
for (int i = sizeAndLength[1]; i < sizeAndLength[0]; i++)
{
if (minHeap.Peek() < array[i])
{
minHeap.DeleteMin();
minHeap.Insert(array[i]);
}
}
List <int> list = new List <int>();
for (int i = 0; i < sizeAndLength[1]; i++)
{
list.Add(minHeap.DeleteMin());
}
list.Reverse();
for (int i = 0; i < list.Count; i++)
{
Console.Write(list[i] + " ");
}
Console.WriteLine();
}
}
