Added titles to READMEs

r1cc4rdo · r1cc4rdo · commit 238dacfde173 · 2020-05-30T02:24:33.000-07:00
diff --git a/README.md b/README.md
@@ -10,6 +10,8 @@ Notes added after examples are comments of mine.
 
 Each problem comes with a description, a unit tests' battery and a solution.
 
+Just looking for a [FizzBuzz](https://wiki.c2.com/?FizzBuzzTest) implementation? Find a few [here](problems/fizzbuzz.py)!
+
 |  # | Description               | Problem                              | Solution                               |
 |----|---------------------------|--------------------------------------|----------------------------------------|
 | 01 | [Interleave the elements of a stack using a queue](problems/01) | [problem](problems/01/problem_01.py) | [solution](problems/01/solution_01.py) |
@@ -63,8 +65,6 @@ Each problem comes with a description, a unit tests' battery and a solution.
 | 49 | [Find the maximum sum of any contiguous subarray](problems/49) | [problem](problems/49/problem_49.py) | [solution](problems/49/solution_49.py) |
 | 50 | [Compute an arithmetic expression tree](problems/50) | [problem](problems/50/problem_50.py) | [solution](problems/50/solution_50.py) |
 
-Just Looking for a [FizzBuzz](https://wiki.c2.com/?FizzBuzzTest) implementation? Find a few [here](problems/fizzbuzz.py)!
-
 ## How to contribute
 
 Pull requests warmly welcomed if you spot issues with any of my solutions!
diff --git a/problems/01/README.md b/problems/01/README.md
@@ -1,4 +1,4 @@
-## [<<](..) Problem 01 [>>](../02)
+## [<<](..) [01] Interleave the elements of a stack using a queue [>>](../02)
 
 Given a stack of N elements, interleave the first half of the stack
 with the second half reversed using one other queue.
diff --git a/problems/02/README.md b/problems/02/README.md
@@ -1,4 +1,4 @@
-## [<<](../01) Problem 02 [>>](../03)
+## [<<](../01) [02] Product of every other number in an array [>>](../03)
 
 Given an array of integers, return a new array such that each element at index i of
 the new array is the product of all the numbers in the original array except the one at i.
diff --git a/problems/03/README.md b/problems/03/README.md
@@ -1,4 +1,4 @@
-## [<<](../02) Problem 03 [>>](../04)
+## [<<](../02) [03] Serialize a tree into a string and back [>>](../04)
 
 Given the root to a binary tree, implement serialize(root), which serializes the tree
 into a string, and deserialize(s), which deserializes the string back into the tree.
diff --git a/problems/04/README.md b/problems/04/README.md
@@ -1,4 +1,4 @@
-## [<<](../03) Problem 04 [>>](../05)
+## [<<](../03) [04] Find the first missing positive integer [>>](../05)
 
 Given an array of integers, find the first missing positive integer in linear time and constant space.
 You can modify the input array in-place.
diff --git a/problems/05/README.md b/problems/05/README.md
@@ -1,4 +1,4 @@
-## [<<](../04) Problem 05 [>>](../06)
+## [<<](../04) [05] Implement Lisp's car and cdr given cons [>>](../06)
 
 cons(a, b) constructs a pair, and car(pair) and cdr(pair) returns the first and last element of that pair.
 
diff --git a/problems/06/README.md b/problems/06/README.md
@@ -1,4 +1,4 @@
-## [<<](../05) Problem 06 [>>](../07)
+## [<<](../05) [06] Implement a XOR linked list [>>](../07)
 
 An XOR linked list is a more memory efficient doubly linked list.
 Instead of each node holding next and prev fields, it holds a field named both, which is a XOR of the next node
diff --git a/problems/07/README.md b/problems/07/README.md
@@ -1,4 +1,4 @@
-## [<<](../06) Problem 07 [>>](../08)
+## [<<](../06) [07] Count the number of decodings for a message [>>](../08)
 
 Given the mapping a = 1, b = 2, ... z = 26, and an encoded message, count the number of ways it can be decoded.
 
diff --git a/problems/08/README.md b/problems/08/README.md
@@ -1,4 +1,4 @@
-## [<<](../07) Problem 08 [>>](../09)
+## [<<](../07) [08] Count the number of unival subtrees [>>](../09)
 
 A unival tree (which stands for "universal value") is a tree where all nodes have the same value.
 Given the root to a binary tree, count the number of unival subtrees.
diff --git a/problems/09/README.md b/problems/09/README.md
@@ -1,4 +1,4 @@
-## [<<](../08) Problem 09 [>>](../10)
+## [<<](../08) [09] Largest sum of non-adjacent numbers [>>](../10)
 
 Given a list of integers, write a function that returns the largest sum of non-adjacent numbers.
 The "largest sum of non-adjacent numbers" is the sum of any subset of non-contiguous elements.
diff --git a/problems/10/README.md b/problems/10/README.md
@@ -1,3 +1,3 @@
-## [<<](../09) Problem 10 [>>](../11)
+## [<<](../09) [10] Call a function after n milliseconds [>>](../11)
 
 Implement a job scheduler which takes in a function f and an integer n, and calls f after n milliseconds.
diff --git a/problems/11/README.md b/problems/11/README.md
@@ -1,4 +1,4 @@
-## [<<](../10) Problem 11 [>>](../12)
+## [<<](../10) [11] Implement an autocomplete system [>>](../12)
 
 Implement an autocomplete system. That is, given a query string s and a dictionary of all possible query strings,
 return all strings in the dictionary that have s as a prefix.
diff --git a/problems/12/README.md b/problems/12/README.md
@@ -1,4 +1,4 @@
-## [<<](../11) Problem 12 [>>](../13)
+## [<<](../11) [12] Count the ways to climb a staircase [>>](../13)
 
 There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time. Given N, write a
 function that returns the number of unique ways you can climb the staircase. The order of the steps matters.
diff --git a/problems/13/README.md b/problems/13/README.md
@@ -1,4 +1,4 @@
-## [<<](../12) Problem 13 [>>](../14)
+## [<<](../12) [13] Longest substring made of k distinct characters [>>](../14)
 
 Given an integer k and a string s, find the length of the longest substring that contains at most k distinct
 characters.
diff --git a/problems/14/README.md b/problems/14/README.md
@@ -1,4 +1,4 @@
-## [<<](../13) Problem 14 [>>](../15)
+## [<<](../13) [14] Monte-Carlo estimate of Pi [>>](../15)
 
 The area of a circle is defined as πr². Estimate π to 3 decimal places using a Monte Carlo method.
 
diff --git a/problems/15/README.md b/problems/15/README.md
@@ -1,4 +1,4 @@
-## [<<](../14) Problem 15 [>>](../16)
+## [<<](../14) [15] Pick a random element from a stream [>>](../16)
 
 Given a stream of elements too large to store in memory, pick a random element from the stream with
 uniform probability.
diff --git a/problems/16/README.md b/problems/16/README.md
@@ -1,4 +1,4 @@
-## [<<](../15) Problem 16 [>>](../17)
+## [<<](../15) [16] Implement an purchase orders' log [>>](../17)
 
 You run a sneaker website and want to record the last N order ids in a log. Implement a data structure to
 accomplish this, with the following API:
diff --git a/problems/17/README.md b/problems/17/README.md
@@ -1,4 +1,4 @@
-## [<<](../16) Problem 17 [>>](../18)
+## [<<](../16) [17] Longest path in a filesystem [>>](../18)
 
 Suppose we represent our file system by a string in the following manner:
 The string "dir\n\tsubdir1\n\tsubdir2\n\t\tfile.ext" represents:
diff --git a/problems/18/README.md b/problems/18/README.md
@@ -1,4 +1,4 @@
-## [<<](../17) Problem 18 [>>](../19)
+## [<<](../17) [18] Max of each sub-array of length k [>>](../19)
 
 Given an array of integers and a number k, where 1 <= k <= length of the array, compute the maximum values of each
 sub-array of length k. Do this in O(n) time and O(k) space. You can modify the input array in-place and you do not
diff --git a/problems/19/README.md b/problems/19/README.md
@@ -1,4 +1,4 @@
-## [<<](../18) Problem 19 [>>](../20)
+## [<<](../18) [19] House coloring problem [>>](../20)
 
 A builder is looking to build a row of N houses that can be of K different colors. He has a goal of minimizing cost
 while ensuring that no two neighboring houses are of the same color. Given an N by K matrix where the nth row and
diff --git a/problems/20/README.md b/problems/20/README.md
@@ -1,4 +1,4 @@
-## [<<](../19) Problem 20 [>>](../21)
+## [<<](../19) [20] Find intersection between single linked lists [>>](../21)
 
 Given two singly linked lists that intersect at some point, find the intersecting node.
 Do this in O(M + N) time (where M and N are the lengths of the lists) and constant space.
diff --git a/problems/21/README.md b/problems/21/README.md
@@ -1,4 +1,4 @@
-## [<<](../20) Problem 21 [>>](../22)
+## [<<](../20) [21] Number of classrooms required given schedule [>>](../22)
 
 Given an array of time intervals (start, end) for classroom lectures (possibly overlapping),
 find the minimum number of rooms required.
diff --git a/problems/22/README.md b/problems/22/README.md
@@ -1,4 +1,4 @@
-## [<<](../21) Problem 22 [>>](../23)
+## [<<](../21) [22] Split a string of words into parts [>>](../23)
 
 Given a dictionary of words and a string made up of those words (no spaces), return the original sentence in a
 list. If there is more than one possible reconstruction, return any of them. If there is no possible
diff --git a/problems/23/README.md b/problems/23/README.md
@@ -1,4 +1,4 @@
-## [<<](../22) Problem 23 [>>](../24)
+## [<<](../22) [23] Solve a maze [>>](../24)[23] Solve a maze./22) [23] Solve a maze [>>](../24)
 
 You are given an M by N matrix consisting of booleans that represents a board. Each True boolean represents a wall.
 Each False boolean represents a tile you can walk on. Given this matrix, a start coordinate, and an end coordinate,
@@ -8,11 +8,10 @@ around the edges of the board.
 
 Examples:
 
-    >>> map = [[False, False, False, False], [True, True, False, True],
-    ...        [False, False, False, False], [False, False, False, False]]
+    >>> matrix = [[False] * 4] * 4
+    >>> matrix[1] = [True, True, False, True]
     >>> coding_problem_23(matrix, (3, 0), (0, 0))
     7
-    
-    >>> map[1][2] = True  # close off path
-    >>> coding_problem_23(matrix, (3, 0), (0, 0))  # returns None
-    
+
+    >>> matrix[1][2] = True  # close off path
+    >>> coding_problem_23(matrix, (3, 0), (0, 0))  # None
diff --git a/problems/24/README.md b/problems/24/README.md
@@ -1,4 +1,4 @@
-## [<<](../23) Problem 24 [>>](../25)
+## [<<](../23) [24] Implement locking in a binary tree [>>](../25)
 
 Implement locking in a binary tree. A binary tree node can be locked or unlocked only if any of its descendants or
 ancestors are not locked. Write a binary tree node class with the following methods:
diff --git a/problems/25/README.md b/problems/25/README.md
@@ -1,4 +1,4 @@
-## [<<](../24) Problem 25 [>>](../26)
+## [<<](../24) [25] Implement regular expression matcher [>>](../26)
 
 Implement regular expression matching with the following special characters:
 
diff --git a/problems/26/README.md b/problems/26/README.md
@@ -1,4 +1,4 @@
-## [<<](../25) Problem 26 [>>](../27)
+## [<<](../25) [26] Remove the kth element from a linked list [>>](../27)
 
 Given a singly linked list and an integer k, remove the kth last element from the list. k is guaranteed to be
 smaller than the length of the list. The list is very long, so making more than one pass is prohibitively expensive.
diff --git a/problems/27/README.md b/problems/27/README.md
@@ -1,4 +1,4 @@
-## [<<](../26) Problem 27 [>>](../28)
+## [<<](../26) [27] Is a string of brackets well-formed? [>>](../28)
 
 Given a string of round, curly, and square open and closing brackets, return whether the brackets are
 balanced (well-formed).
diff --git a/problems/28/README.md b/problems/28/README.md
@@ -1,4 +1,4 @@
-## [<<](../27) Problem 28 [>>](../29)
+## [<<](../27) [28] Write an algorithm to justify text [>>](../29)
 
 Write an algorithm to justify text.
 
diff --git a/problems/29/README.md b/problems/29/README.md
@@ -1,4 +1,4 @@
-## [<<](../28) Problem 29 [>>](../30)
+## [<<](../28) [29] Run-length encoding and decoding [>>](../30)
 
 Run-length encoding is a fast and simple method of encoding strings. The basic idea is to represent repeated
 successive characters as a single count and character. Implement run-length encoding and decoding. You can assume
diff --git a/problems/30/README.md b/problems/30/README.md
@@ -1,4 +1,4 @@
-## [<<](../29) Problem 30 [>>](../31)
+## [<<](../29) [30] Water trapped in an elevation map [>>](../31)
 
 You are given an array of non-negative integers that represents a two-dimensional elevation map where each element
 is unit-width wall and the integer is the height. Suppose it will rain and all spots between two walls get filled
diff --git a/problems/31/README.md b/problems/31/README.md
@@ -1,4 +1,4 @@
-## [<<](../30) Problem 31 [>>](../32)
+## [<<](../30) [31] Compute the edit distance between two strings [>>](../32)
 
 Given two strings, compute the edit distance between them.
 
diff --git a/problems/32/README.md b/problems/32/README.md
@@ -1,4 +1,4 @@
-## [<<](../31) Problem 32 [>>](../33)
+## [<<](../31) [32] Possibility of arbitration in currency exchange [>>](../33)
 
 Suppose you are given a table of currency exchange rates, represented as a 2D array. Determine whether there is a
 possible arbitrage: that is, whether there is some sequence of trades you can make, starting with some amount A of
diff --git a/problems/33/README.md b/problems/33/README.md
@@ -1,4 +1,4 @@
-## [<<](../32) Problem 33 [>>](../34)
+## [<<](../32) [33] Compute the running median of a sequence of numbers [>>](../34)
 
 Compute the running median of a sequence of numbers. That is, given a stream of numbers, print out the median of
 the list so far on each new element. Recall that the median of an even-numbered list is the average of the two
diff --git a/problems/34/README.md b/problems/34/README.md
@@ -1,4 +1,4 @@
-## [<<](../33) Problem 34 [>>](../35)
+## [<<](../33) [34] Fewest characters to make a palindrome [>>](../35)
 
 Given a string, find the palindrome that can be made by inserting the fewest number of characters as possible
 anywhere in the word. If there is more than one palindrome of minimum length that can be made, return the
diff --git a/problems/35/README.md b/problems/35/README.md
@@ -1,4 +1,4 @@
-## [<<](../34) Problem 35 [>>](../36)
+## [<<](../34) [35] Segregate the values of an array [>>](../36)
 
 Given an array of strictly the characters 'R', 'G', and 'B', segregate the values of the array so that all the 'R's
 come first, the 'G's come second, and the 'B's come last. You can only swap elements of the array.
diff --git a/problems/36/README.md b/problems/36/README.md
@@ -1,4 +1,4 @@
-## [<<](../35) Problem 36 [>>](../37)
+## [<<](../35) [36] Find the second largest node in the tree [>>](../37)
 
 Given the root to a binary search tree, find the second largest node in the tree.
 
diff --git a/problems/37/README.md b/problems/37/README.md
@@ -1,4 +1,4 @@
-## [<<](../36) Problem 37 [>>](../38)
+## [<<](../36) [37] Generate the power set of a set [>>](../38)
 
 The power set of a set is the set of all its subsets. Write a function that, given a set, generates its power set.
 You may also use a list or array to represent a set.
diff --git a/problems/38/README.md b/problems/38/README.md
@@ -1,4 +1,4 @@
-## [<<](../37) Problem 38 [>>](../39)
+## [<<](../37) [38] Solve the N-queens problem [>>](../39)
 
 You have an N by N board. Write a function that, given N, returns the number of possible arrangements of the board
 where N queens can be placed on the board without threatening each other, i.e. no two queens share the same row,
diff --git a/problems/39/README.md b/problems/39/README.md
@@ -1,4 +1,4 @@
-## [<<](../38) Problem 39 [>>](../40)
+## [<<](../38) [39] Implement Conway's Game of Life [>>](../40)
 
 Conway's Game of Life takes place on an infinite two-dimensional board of square cells. Each cell is either dead or
 alive, and at each tick, the following rules apply:
diff --git a/problems/40/README.md b/problems/40/README.md
@@ -1,4 +1,4 @@
-## [<<](../39) Problem 40 [>>](../41)
+## [<<](../39) [40] Find the non-duplicated integer [>>](../41)
 
 Given an array of integers where every integer occurs three times except for one integer, which only occurs once,
 find and return the non-duplicated integer. Do this in O(N) time and O(1) space.
diff --git a/problems/41/README.md b/problems/41/README.md
@@ -1,4 +1,4 @@
-## [<<](../40) Problem 41 [>>](../42)
+## [<<](../40) [41] Itinerary from flights' list [>>](../42)
 
 Given an unordered list of flights taken by someone, each represented as (origin, destination) pairs, and a
 starting airport, compute the person's itinerary. If no such itinerary exists, return null. If there are multiple
diff --git a/problems/42/README.md b/problems/42/README.md
@@ -1,4 +1,4 @@
-## [<<](../41) Problem 42 [>>](../43)
+## [<<](../41) [42] Subset of an array that adds up to k [>>](../43)
 
 Given a list of integers S and a target number k, write a function that returns a subset of S that adds up to k.
 If such a subset cannot be made, then return null.
diff --git a/problems/43/README.md b/problems/43/README.md
@@ -1,4 +1,4 @@
-## [<<](../42) Problem 43 [>>](../44)
+## [<<](../42) [43] Implement a stack with a ma [>>](../44)
 
 Implement a stack that has the following methods:
 
diff --git a/problems/44/README.md b/problems/44/README.md
@@ -1,4 +1,4 @@
-## [<<](../43) Problem 44 [>>](../45)
+## [<<](../43) [44] Determine how "out of order" an array A is [>>](../45)
 
 We can determine how "out of order" an array A is by counting the number of inversions it has. Two elements A[i]
 and A[j] form an inversion if A[i] > A[j] but i < j. That is, a smaller element appears after a larger element.
diff --git a/problems/45/README.md b/problems/45/README.md
@@ -1,4 +1,4 @@
-## [<<](../44) Problem 45 [>>](../46)
+## [<<](../44) [45] Implement rand [>>](../46)
 
 Using a function rand5() that returns an integer from 1 to 5 (inclusive) with uniform probability, implement a
 function rand7() that returns an integer from 1 to 7 (inclusive).
diff --git a/problems/46/README.md b/problems/46/README.md
@@ -1,4 +1,4 @@
-## [<<](../45) Problem 46 [>>](../47)
+## [<<](../45) [46] Find the longest contiguous palindrome [>>](../47)
 
 Given a string, find the longest palindromic contiguous substring. If there are more than one with the maximum
 length, return any one.
diff --git a/problems/47/README.md b/problems/47/README.md
@@ -1,4 +1,4 @@
-## [<<](../46) Problem 47 [>>](../48)
+## [<<](../46) [47] Max profit from a stock time-series [>>](../48)
 
 Given a array of numbers representing the stock prices of a company in chronological order, write a function that
 calculates the maximum profit you could have made from buying and selling that stock once. You must buy before you
diff --git a/problems/48/README.md b/problems/48/README.md
@@ -1,4 +1,4 @@
-## [<<](../47) Problem 48 [>>](../49)
+## [<<](../47) [48] Reconstruct tree from pre-order and in-order traversals [>>](../49)
 
 Given pre-order and in-order traversals of a binary tree, write a function to reconstruct the tree.
 
diff --git a/problems/49/README.md b/problems/49/README.md
@@ -1,4 +1,4 @@
-## [<<](../48) Problem 49 [>>](../50)
+## [<<](../48) [49] Find the maximum sum of any contiguous subarray [>>](../50)
 
 Given an array of numbers, find the maximum sum of any contiguous subarray of the array.
 For example, given the array [34, -50, 42, 14, -5, 86], the maximum sum would be 137, since we would take elements
diff --git a/problems/50/README.md b/problems/50/README.md
@@ -1,4 +1,4 @@
-## [<<](../49) Problem 50 [>>](../51)
+## [<<](../49) [50] Compute an arithmetic expression tree [>>](../51)
 
 Suppose an arithmetic expression is given as a binary tree. Each leaf is an integer and each internal node
 is one of '+', '-', '*' or '/'. Given the root to such a tree, write a function to evaluate it.
