Binary Search

Left-mid:
  mid = lo + (hi-lo) / 2
  lo = mid + 1
  hi = mid
Right-mid
  mid = lo + (hi - lo + 1) / 2
  lo = mid
  hi = mid - 1

Detecting Cycle

dfs way of checking

def dfs( node ):
  # node are in our current path, cycle detected
  if visited[node] == 2: return False
  # node have been previous passed, it's okay to visit
  if visited[node] == 1: Return True
  visited[node] = 2 # Mark Node to currently visiting
  for next in connected[node]:
    if not dfs(next):
      return False
  visited[node] = 1 # Mark Node to been visited
  return True

BitMask

#Same as getting all permutation of N value
for mask in range(1 << N):
  print(mask, bin(mask))

#Going through the Binary and see which index is in our creent permutation
for x in range(N):
  print("\t", ((mask >> x) & 1))

Binary Index Tree

class bit():
  def __init__(self):
    self.size = (10**5) + 1
    self.arr = [0] * self.size
  def prefix_sum(self, idx):
    res = 0
    while idx > 0:
      res += self.arr[idx]
      idx -= idx & -idx
    return res
  def increase(self, idx, delta):
    while idx <= self.size:
      self.arr[idx] += delta
      idx += idx & -idx
  def range_sum(self, l, r): 
    return self.prefix_sum(r) - self.prefix_sum(l - 1);

KMP

def strStr(self, haystack: str, needle: str) -> int:
    if needle == "": return 0
    if haystack == "": return -1
    suffix = self.suffix_array(needle, len(needle))
    kmp = [0] * len(haystack)
    kmp[0] = 1 if haystack[0] == needle[0] else 0
    if len(needle) == 1 and kmp[0] == 1:
        return 0
    for i in range(1,len(haystack)):
        j = kmp[i-1]
        while j > 0 and haystack[i] != needle[j]:
            j = suffix[j-1]
        if haystack[i] == needle[j]:
            kmp[i] = j + 1
        if kmp[i] == len(needle):
            return i - len(needle) + 1
    return -1

# The maximum length k so that p[0:k-1] = p [p-k+1:i]
# https://github.com/wisdompeak/LeetCode/tree/master/String/1392.Longest-Happy-Prefix
# https://github.com/wisdompeak/LeetCode/tree/master/String/028.Implement-strStr
def suffix_array(self, needle, size):
    suffix = [0] * size
    for i in range(1, size):
        j = suffix[i-1]
        while j > 0 and needle[i] != needle[j]:
            j = suffix[j-1]
        if needle[i] == needle[j]:
            suffix[i] = j + 1
    return suffix

Name		Name	Last commit message	Last commit date
Latest commit History 448 Commits
.vscode		.vscode
C++ Primer		C++ Primer
CodeForces		CodeForces
CodeWar		CodeWar
Codeforces		Codeforces
Codility		Codility
HackerRank		HackerRank
Python		Python
USACO		USACO
UVA		UVA
codeforces		codeforces
.DS_Store		.DS_Store
002_Add_Two_Number_v2.cpp		002_Add_Two_Number_v2.cpp
003_Longest_Substring_Without_Repeating_Characters.cpp		003_Longest_Substring_Without_Repeating_Characters.cpp
004_Median_Of_Two_Sorted_Arrays.cpp		004_Median_Of_Two_Sorted_Arrays.cpp
005_Longest_Palindromic_Substring.cpp		005_Longest_Palindromic_Substring.cpp
006_ZigZag_Conversion.cpp		006_ZigZag_Conversion.cpp
007_Reverse_integer.cpp		007_Reverse_integer.cpp
008_String_To_Integer.cpp		008_String_To_Integer.cpp
009_Palindrome_Number.cpp		009_Palindrome_Number.cpp
010_regular_Expression_Matching.cpp		010_regular_Expression_Matching.cpp
0117_Populating_Next_Right_Pointers_In_Each_Node_II.cpp		0117_Populating_Next_Right_Pointers_In_Each_Node_II.cpp
011_Container_With_Most_Water.cpp		011_Container_With_Most_Water.cpp
012_Integer_To_Roman.cpp		012_Integer_To_Roman.cpp
013_Roman_To_Integer.cpp		013_Roman_To_Integer.cpp
0148_Sort_List_Bottom_Up.cpp		0148_Sort_List_Bottom_Up.cpp
0148_Sort_List_Top_Down.cpp		0148_Sort_List_Top_Down.cpp
014_Longest_Common_Prefix.cpp		014_Longest_Common_Prefix.cpp
015_3Sum.cpp		015_3Sum.cpp
016_3Sum_Closest.cpp		016_3Sum_Closest.cpp
017_Letter_Combinations_Of_A_Phone_Number.cpp		017_Letter_Combinations_Of_A_Phone_Number.cpp
018_4Sum.cpp		018_4Sum.cpp
019_Remove_Nth_Node_From_End_Of_List.cpp		019_Remove_Nth_Node_From_End_Of_List.cpp
020_Valid_Parentheses.cpp		020_Valid_Parentheses.cpp
0211_Add_And_Search_Word.cpp		0211_Add_And_Search_Word.cpp
021_Merge_Two_Sorted_Lists.cpp		021_Merge_Two_Sorted_Lists.cpp
022_Generate_Parentheses.cpp		022_Generate_Parentheses.cpp
0231_Power_Of_Two.cpp		0231_Power_Of_Two.cpp
023_Merge_K_Sorted_Lists.cpp		023_Merge_K_Sorted_Lists.cpp
023_Merge_K_Sorted_Lists_Divide_And_Qu.cpp		023_Merge_K_Sorted_Lists_Divide_And_Qu.cpp
024_Swap_Nodes_In_Pairs.cpp		024_Swap_Nodes_In_Pairs.cpp
024_Swap_Nodes_In_Pairs.py		024_Swap_Nodes_In_Pairs.py
025_Reverse_Nodes_In_Kth_Group.cpp		025_Reverse_Nodes_In_Kth_Group.cpp
026_Remove_Duplicates_From_Sorted_Array.cpp		026_Remove_Duplicates_From_Sorted_Array.cpp
026v2_Remove_Duplicates_From_Sorted_Array.cpp		026v2_Remove_Duplicates_From_Sorted_Array.cpp
027_Remove_Element.cpp		027_Remove_Element.cpp
027v2_Remove_Element.cpp		027v2_Remove_Element.cpp
0289_Game_Of_Life.cpp		0289_Game_Of_Life.cpp
028_Implement_strStr.cpp		028_Implement_strStr.cpp
029_Divide_Two_Integers.cpp		029_Divide_Two_Integers.cpp
030_Substring_With_Concatenation_Of_All_Words.cpp		030_Substring_With_Concatenation_Of_All_Words.cpp
0312_Burst_Balloons.cpp		0312_Burst_Balloons.cpp
031_Next_Permutation.cpp		031_Next_Permutation.cpp
032_Longest_Valid_Parentheses.cpp		032_Longest_Valid_Parentheses.cpp
033_Search_In_Rotated_Sorted_Array.cpp		033_Search_In_Rotated_Sorted_Array.cpp
036_Valid_Sudoku.cpp		036_Valid_Sudoku.cpp
036_Valid_Sudokuv2.cpp		036_Valid_Sudokuv2.cpp
037_Sudoku_Solver.cpp		037_Sudoku_Solver.cpp
038_Count_And_String.cpp		038_Count_And_String.cpp
039_Combination_Sum.cpp		039_Combination_Sum.cpp
040_Combination_Sum_II.cpp		040_Combination_Sum_II.cpp
041_First_Missing_Positive.cpp		041_First_Missing_Positive.cpp
0424_Longest_Repeating_Character_Replacement.cpp		0424_Longest_Repeating_Character_Replacement.cpp
042_Trapping_Rain_Water.cpp		042_Trapping_Rain_Water.cpp
043_Multiply_Strings.cpp		043_Multiply_Strings.cpp
044_Wildcard_Matching.cpp		044_Wildcard_Matching.cpp
045_Jump_Game_II.cpp		045_Jump_Game_II.cpp
0467B_Fedor_And_New_Game.cpp		0467B_Fedor_And_New_Game.cpp
048_Rotate_Image.cpp		048_Rotate_Image.cpp
051_N_Queens.cpp		051_N_Queens.cpp
051_N_Queens_v2.cpp		051_N_Queens_v2.cpp
052_N_Queens_II.cpp		052_N_Queens_II.cpp
056_Merge_Intervals.cpp		056_Merge_Intervals.cpp
057_Insert_Interval.cpp		057_Insert_Interval.cpp
059_Sprial_Matrix_II.cpp		059_Sprial_Matrix_II.cpp
064_Minimum_Path_Sum.cpp		064_Minimum_Path_Sum.cpp
065_Valid_Number.cpp		065_Valid_Number.cpp
0662v2_Maximum_Width_Of_Binary_Tree.cpp		0662v2_Maximum_Width_Of_Binary_Tree.cpp
067_Add_Binary.cpp		067_Add_Binary.cpp
071_Simplify_Path.cpp		071_Simplify_Path.cpp
071_Simplify_Path2.cpp		071_Simplify_Path2.cpp
072_Edit_Distance.cpp		072_Edit_Distance.cpp
0732A_Buy_A_Shovel.cpp		0732A_Buy_A_Shovel.cpp
0741_Cherry_Pickup.cpp		0741_Cherry_Pickup.cpp
076_Minimum_Window_Substring.cpp		076_Minimum_Window_Substring.cpp
078_Subsets.cpp		078_Subsets.cpp
079_Longest_Common_Substring.cpp		079_Longest_Common_Substring.cpp
080v2_Remove_Duplicates_From_Sorted_Array_II.cpp		080v2_Remove_Duplicates_From_Sorted_Array_II.cpp
081_Search_In_Rotated_Sorted_Array_II.cpp		081_Search_In_Rotated_Sorted_Array_II.cpp
082_Remove_Duplicates_From_Sorted_List_II.cpp		082_Remove_Duplicates_From_Sorted_List_II.cpp
0857_Minimum_Cost_To_Hire_K_Worker.cpp		0857_Minimum_Cost_To_Hire_K_Worker.cpp
086_Partition_List.cpp		086_Partition_List.cpp
086_Partition_List_II.cpp		086_Partition_List_II.cpp
089_Gray_Code.cpp		089_Gray_Code.cpp
0904_Fruit_Into_Baskets.cpp		0904_Fruit_Into_Baskets.cpp
090_Subsets_II.cpp		090_Subsets_II.cpp
091_Decode_Ways.cpp		091_Decode_Ways.cpp
092_Reverse_Linked_List_II.cpp		092_Reverse_Linked_List_II.cpp
0957_Prison_Cells_After_N_Days.cpp		0957_Prison_Cells_After_N_Days.cpp
095_Unique_binary_Search_Trees_II.cpp		095_Unique_binary_Search_Trees_II.cpp

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