update bunch2

README.md

@@ -7,45 +7,109 @@ List of Implementations:
 ```
 .
 ├── array
+│   ├── circular_counter.py
+│   ├── flatten.py
 │   ├── garage.py
-│   ├── house_robber.py
-│   ├── longest_increasing_subsequence.py
 │   ├── longest_non_repeat.py
+│   ├── merge_intervals.py
+│   ├── missing_ranges.py
 │   ├── plus_one.py
-│   └── wiggle_sort.py
+│   ├── rotate_array.py
+│   ├── summary_ranges.py
+│   ├── three_sum.py
+│   └── two_sum.py
 ├── backtrack
 │   ├── anagram.py
+│   ├── array_sum_combinations.py
 │   ├── combination_sum.py
+│   ├── expression_add_operators.py
+│   ├── factor_combinations.py
+│   ├── general_solution.md
+│   ├── generate_abbreviations.py
+│   ├── generate_parenthesis.py
+│   ├── letter_combination.py
 │   ├── palindrome_partitioning.py
+│   ├── pattern_match.py
 │   ├── permute.py
 │   ├── permute_unique.py
 │   ├── subsets.py
 │   └── subsets_unique.py
 ├── bfs
-│   └── shortest_distance_from_all_buildings.py
-├── divide-and-conquer
-│   ├── expression-add-operators.py
-│   └── the-skyline-problem.py
+│   ├── shortest_distance_from_all_buildings.py
+│   └── word_ladder.py
+├── bit
+│   ├── count_ones.py
+│   ├── power_of_two.py
+│   ├── reverse_bits.py
+│   ├── single_number2.py
+│   ├── single_number.py
+│   └── subsets.py
+├── design
+│   ├── alarm_system.md
+│   ├── all_o_one_ds.md
+│   ├── calculator.md
+│   ├── excel_table.md
+│   ├── LRUcache.md
+│   ├── nearby_drivers.md
+│   ├── ride_sharing.md
+│   ├── task_runner.md
+│   └── twitter_feeds.md
+├── dfs
+│   ├── all_factors.py
+│   ├── count_islands.py
+│   ├── pacific_atlantic.py
+│   ├── sudoku_solver.py
+│   └── walls_and_gates.py
 ├── dp
+│   ├── buy_sell_stock.py
+│   ├── climbing_stairs.py
+│   ├── combination_sum.py
+│   ├── house_robber.py
+│   ├── longest_increasing.py
+│   ├── max_product_subarray.py
 │   ├── max_subarray.py
+│   ├── num_decodings.py
+│   ├── regex_matching.py
 │   └── word_break.py
 ├── graph
+│   ├── clone_graph.py
 │   ├── find_path.py
 │   ├── graph.py
 │   └── traversal.py
-├── hashtable
-│   └── hashtable.py
+├── heap
+│   ├── merge_sorted_k_lists.py
+│   ├── skyline.py
+│   └── sliding_window_max.py
 ├── linkedlist
+│   ├── add_two_numbers.py
+│   ├── copy_random_pointer.py
+│   ├── delete_node.py
 │   ├── first_cyclic_node.py
+│   ├── is_cyclic.py
 │   ├── is_palindrome.py
 │   ├── kth_to_last.py
 │   ├── linkedlist.py
-│   └── remove_duplicates.py
+│   ├── remove_duplicates.py
+│   ├── reverse.py
+│   ├── rotate_list.py
+│   └── swap_in_pairs.py
+├── map
+│   ├── hashtable.py
+│   ├── longest_common_subsequence.py
+│   ├── randomized_set.py
+│   └── valid_sudoku.py
+├── math
+│   ├── generate_strobogrammtic.py
+│   ├── is_strobogrammatic.py
+│   ├── nth_digit.py
+│   └── sqrt_precision_factor.py
 ├── matrix
 │   ├── bomb_enemy.py
 │   ├── matrix_rotation.txt
-│   └── pacific_atlantic.py
-├── out.txt
+│   ├── rotate_image.py
+│   ├── sparse_dot_vector.py
+│   ├── sparse_mul.py
+│   └── spiral_traversal.py
 ├── queue
 │   ├── __init__.py
 │   ├── max_sliding_window.py
@@ -59,56 +123,88 @@ List of Implementations:
 │   ├── count_elem.py
 │   ├── first_occurance.py
 │   └── last_occurance.py
-├── sorting
+├── set
+│   └── randomized_set.py
+├── sort
 │   ├── insertion_sort.py
+│   ├── meeting_rooms.py
 │   ├── merge_sort.py
 │   ├── quick_sort.py
 │   ├── selection_sort.py
-│   └── sort_colors.py
+│   ├── sort_colors.py
+│   ├── topsort.py
+│   └── wiggle_sort.py
 ├── stack
 │   ├── __init__.py
 │   ├── __init__.pyc
 │   ├── longest_abs_path.py
 │   ├── __pycache__
 │   │   ├── __init__.cpython-35.pyc
 │   │   └── stack.cpython-35.pyc
+│   ├── simplify_path.py
 │   ├── stack.py
-│   └── stack.pyc
+│   ├── stack.pyc
+│   └── valid_parenthesis.py
 ├── string
+│   ├── add_binary.py
+│   ├── breaking_bad.py
 │   ├── decode_string.py
 │   ├── encode_decode.py
+│   ├── group_anagrams.py
+│   ├── int_to_roman.py
+│   ├── is_palindrome.py
 │   ├── license_number.py
-│   ├── missing_ranges.py
+│   ├── make_sentence.py
+│   ├── multiply_strings.py
+│   ├── one_edit_distance.py
 │   ├── rabin_karp.py
 │   ├── reverse_string.py
 │   ├── reverse_vowel.py
 │   ├── reverse_words.py
+│   ├── roman_to_int.py
 │   └── word_squares.py
-├── tests
-│   └── test_stack.py
+├── tmp
+│   └── temporary.md
 ├── tree
-│   ├── array2bst.py
+│   ├── binary_tree_paths.py
 │   ├── bintree2list.py
-│   ├── bst_closest_value.py
-│   ├── BSTIterator.py
+│   ├── bst
+│   │   ├── array2bst.py
+│   │   ├── bst_closest_value.py
+│   │   ├── BSTIterator.py
+│   │   ├── delete_node.py
+│   │   ├── is_bst.py
+│   │   ├── kth_smallest.py
+│   │   ├── lowest_common_ancestor.py
+│   │   ├── predecessor.py
+│   │   ├── serialize_deserialize.py
+│   │   ├── successor.py
+│   │   └── unique_bst.py
 │   ├── deepest_left.py
 │   ├── invert_tree.py
 │   ├── is_balanced.py
 │   ├── is_subtree.py
 │   ├── is_symmetric.py
 │   ├── longest_consecutive.py
+│   ├── lowest_common_ancestor.py
 │   ├── max_height.py
 │   ├── max_path_sum.py
 │   ├── min_height.py
-│   ├── predecessor.py
+│   ├── path_sum2.py
+│   ├── path_sum.py
+│   ├── pretty_print.py
 │   ├── same_tree.py
-│   ├── successor.py
-│   └── tree.py
-└── trie
-    ├── add_and_search.py
-    └── trie.py
-
-
+│   ├── traversal
+│   │   ├── inorder.py
+│   │   ├── level_order.py
+│   │   └── zigzag.py
+│   ├── tree.py
+│   └── trie
+│       ├── add_and_search.py
+│       └── trie.py
+├── tree.md
+└── union-find
+    └── count_islands.py
 
 ```
 

array/circular_counter.py

@@ -0,0 +1,46 @@
+"""
+There are people sitting in a circular fashion,
+print every third member while removing them,
+the next counter starts immediately after the member is removed.
+Print till all the members are exhausted.
+
+For example:
+Input: consider 123456789 members sitting in a circular fashion,
+Output: 369485271
+"""
+
+a = ['1','2','3','4','5','6','7','8','9']
+
+def josepheus(int_list, skip):
+  skip = skip - 1 #list starts with 0 index
+  idx = 0
+  while len(int_list)>0:
+    idx = (skip+idx)%len(int_list) #hashing to keep changing the index to every 3rd
+    print int_list.pop(idx)
+
+
+josepheus(a,3)
+
+"""
+the reason for hashing is that we have to find the index of the item which needs to be removed.
+So for e.g. if you iterate with the initial list of folks with every 3rd item eliminated:
+
+INPUT
+int_list = 123456789
+skip = 3
+
+While Iteration:
+
+int_list = 123456789
+len(int_list) = 9
+skip = 2 # as int_list starts from 0
+idx = (0 + 2) % 9 #here previous index was 0
+so 3rd element which is 3 in this case eliminated
+int_list = 12456789
+len(int_list) = 8
+idx = (2 + 2) % 8 #here previous index was 2
+so 3rd element starting from 4th person which is 6 would be deleted.
+and so on
+The reason why we have to do this way is I am not putting the people who escape at the back of list so ideally in 2 while iteration the list should have been
+45678912 and then no hashing needed to be done, which means you can directly remove the third element
+"""

array/flatten.py

@@ -0,0 +1,60 @@
+"""
+Implement Flatten Arrays.
+Given an array that may contain nested arrays,
+give a single resultant array.
+
+function flatten(input){
+}
+
+Example:
+
+Input: var input = [2, 1, [3, [4, 5], 6], 7, [8]];
+flatten(input);
+Output: [2, 1, 3, 4, 5, 6, 7, 8]
+"""
+
+
+def list_flatten(l, a=None):
+    # check a
+    if a is None:
+        # initialize with empty list
+        a = []
+
+    for i in l:
+        if isinstance(i, list):
+            list_flatten(i, a)
+        else:
+            a.append(i)
+    return a
+
+
+# stack version
+# public static List<Integer> flatten(List<NestedList> l) {
+# List<Integer> main = new ArrayList<Integer>();
+		# Stack<List<NestedList>> stack = new Stack<List<NestedList>>();
+		# Stack<Integer> indexes = new Stack<Integer>();
+		# stack.add(l);
+		# indexes.add(0);
+		# while (true) {
+			# if (stack.isEmpty())
+				# break;
+			# int index1 = indexes.pop();
+			# l = stack.pop();
+			# for (int i = index1; i < l.size(); i++) {
+				# NestedList n = l.get(i);
+				# if (n.isInteger()) {
+					# main.add(n.value);
+				# } else {
+					# stack.add(l);
+					# indexes.add(i+1);
+					# l = n.list;
+					# stack.add(l);
+					# indexes.add(0);
+					# break;
+
+				# }
+			# }
+		# }
+
+		# return main;
+# }

array/summary_ranges.py

@@ -0,0 +1,27 @@
+"""
+Given a sorted integer array without duplicates,
+return the summary of its ranges.
+
+For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].
+"""
+
+
+def summary_ranges(nums):
+    """
+    :type nums: List[int]
+    :rtype: List[str]
+    """
+    res = []
+    if len(nums) == 1:
+        return [str(nums[0])]
+    i = 0
+    while i < len(nums):
+        num = nums[i]
+        while i+1 < len(nums) and nums[i+1] - nums[i] == 1:
+            i += 1
+        if nums[i] != num:
+            res.append(str(num) + "->" + str(nums[i]))
+        else:
+            res.append(str(num))
+        i += 1
+    return res