Initial commit with solutions.

easy/count_and_say.py

@@ -0,0 +1,32 @@
+class Solution:
+    def countAndSay(self, n):
+        """
+        :type n: int
+        :rtype: str
+        """
+        ret = "1"
+        for i in range(n):
+            latest = ""
+            if i < 1:
+                next
+            else:
+                c = ret[0]
+                count = 0
+                for j in range(len(ret)):
+                    print "i: " + str(i) + " latest: '" + latest + "'"
+                    if ret[j] == c:
+                        print "count (" + str(count) + ") += 1"
+                        count += 1
+                    else:
+                        # convert 'count' integer to string
+                        latest = latest + str(count) + c
+                        print "else: " + latest
+                        c = ret[j]
+                        count = 1
+                latest = latest + str(count) + c
+                ret = latest
+        return ret
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.countAndSay(5))

easy/count_and_say.py~

@@ -0,0 +1,29 @@
+class Solution:
+    def countAndSay(self, n):
+        """
+        :type n: int
+        :rtype: str
+        """
+        ret = "1"
+        for i in range(n):
+            latest = ""
+            if i < 2:
+                next
+            else:
+                c = ret[0]
+                latest = ""
+                count = 0
+                for j in range(len(ret)):
+                    if ret[j] == c and j < len(ret) - 1:
+                        count += 1
+                    else:
+                        # convert 'count' integer to string
+                        latest = latest + str(count) + c
+                        c = ret[j]
+                        count = 1
+                    ret = latest
+        return ret
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.countAndSay(1))

easy/palindrome.py

@@ -0,0 +1,15 @@
+class Solution:
+    def isPalindrome(self, x):
+        """
+        :type x: int
+        :rtype: bool
+        """
+        if x < 0:
+            return False
+        y = x
+        accum = 0
+        while y > 0:
+            j = y % 10
+            y = int(y / 10)
+            accum = (accum * 10) + j
+        return accum == x

easy/remove-duplicates/sub.rb

@@ -0,0 +1,21 @@
+# @param {Integer[]} nums
+# @return {Integer}
+def remove_duplicates(nums)
+  start = -Float::INFINITY
+  (0..nums.size-1).each do |i|
+    swapped = false
+    (i..nums.size-1).each do |j|
+      if nums[j] > start then
+        start = nums[i] = nums[j]
+        swapped = true
+        break
+      end
+    end
+    return i unless swapped
+  end
+  return nums.size
+end
+
+
+remove_duplicates([0,0,1,1,1,2,2,3,3,4])
+remove_duplicates([1,1,2])

easy/remove-duplicates/sub.rb~

@@ -0,0 +1,32 @@
+# @param {Integer[]} nums
+# @return {Integer}
+def remove_duplicates(nums)
+  print nums
+  (0..nums.size-1).each do |i|
+    if nums[i].nil? then
+      j = i
+      loop do
+        j += 1
+        if !nums[j].nil?
+          nums[i] = nums[j]
+          break
+        end
+      end
+      return i
+    end
+
+    j = i
+    loop do
+      j += 1
+      break if j == nums.size-1
+      break if nums[j] > nums[i]
+      nums[j] = nil if nums[j] == nums[i]
+    end
+
+  end
+  return nums.size
+end
+
+
+remove_duplicates([0,0,1,1,1,2,2,3,3,4])
+#remove_duplicates([1,1,2])  # => 1

easy/rotate-array/sub.rb

@@ -0,0 +1,17 @@
+# https://leetcode.com/explore/interview/card/top-interview-questions-easy/92/array/646/
+
+def rotate(nums, k)
+  k.times do
+    tmp = nums[nums.size-1]
+    (nums.size-1).downto(1).each do |i|
+      nums[i] = nums[i-1]
+    end
+    nums[0] = tmp
+  end
+end
+
+
+nums = [1,2,3,4,5,6]
+rotate(nums, 2)
+print nums
+

easy/valid-parentheses/sub.rb

@@ -0,0 +1,27 @@
+# @param {String} s
+# @return {Boolean}
+def is_valid(s)
+  st = []
+  s.split('').each do |c|
+    case c
+    when '('
+      st << ')'
+    when '['
+      st << ']'
+    when '{'
+      st << '}'
+    else
+      if c == st[-1]
+        st.pop
+      else
+        return false
+      end
+    end
+  end
+  st.empty?
+end
+
+is_valid("[")
+# is_valid("(]")
+# is_valid("()[]{}")
+# is_valid("{[]}")

easy/valid-parentheses/sub.rb~

@@ -0,0 +1,27 @@
+# @param {String} s
+# @return {Boolean}
+def is_valid(s)
+  st = []                   # => []
+  s.split('').each do |c|   # => ["(", ")"]
+    case c                  # => "("
+    when '('
+      st << ')'             # => [")"]
+      break
+    when '['
+      st << ']'
+      next
+    when '{'
+      st << '}'
+      next
+    else
+      if c == st[-1]
+        st.pop!
+      else
+        return false
+      end
+    end
+  end                       # => nil
+  return true if st.empty?  # => false
+end                         # => :is_valid
+
+is_valid("()")  # => nil

google/k_empty_slots.rb

@@ -0,0 +1,32 @@
+# @param {Integer[]} flowers
+# @param {Integer} k
+# @return {Integer}
+def k_empty_slots(flowers, k)
+  (0..flowers.size-k-2).each do |left|                                          # => 0..6
+    right = left + k + 1                                                        # => 3,    4
+    found = true                                                                # => true, true
+    (left+1..right-1).each do |middle|                                          # => 1..2, 2..3
+      found = false if flowers[middle].between?(flowers[left], flowers[right])  # => nil, false, nil, nil
+    end                                                                         # => 1..2, 2..3
+
+    puts [left, right] if found                          # => nil,   nil
+    puts [flowers[left], flowers[right]] if found        # => nil,   nil
+    puts [flowers[left], flowers[right]].max if found    # => nil,   nil
+    return [flowers[left], flowers[right]].max if found  # => false, true
+  end
+  return -1
+end                                                      # => :k_empty_slots
+
+#k_empty_slots([1,3,2], 1)          # => 2
+#k_empty_slots([1,2,3], 1)          # => -1
+#k_empty_slots([1,2,3,4,5,7,6], 1)
+k_empty_slots([6,5,8,9,7,1,10,2,3,4],2)  # => 7
+
+puts (5..3)  # => nil
+
+# >> 1
+# >> 4
+# >> 5
+# >> 7
+# >> 7
+# >> 5..3

hard/#valid_num.rb#

@@ -0,0 +1,40 @@
+
+def is_number(s)
+  return true if /^\s*\+\.\d+/ =~ s
+  return false if /\..*\./ =~ s
+  return false if /^\s*\d+e\d+\.\d+$/ =~ s
+  return true if /^\s*\.\d+\s*$/ =~ s
+  return false if (/^\s*\.\s*$/ =~ s) or (/^\s*$/ =~ s) or (/^\s*\.+.*\s*$/ =~ s) or
+    (/^\s*e\d+\s*$/ =~ s)
+
+  0 == (/^\s*(?!e)(?!\+\.)(?!\-\-)(?!\-\+)([+-]\d)?\d*\.?(\.\d)?\d*([e]\d)?(e[+-]\d+)?\d*\.?(\d*)?\s*$/ =~ s)
+end
+
+
+/^\s*(?!e)(?!-)(?![-+])([+-]\d)?\d*(\.\d)?\d*+([e]\d)?(e[+-]\d+)?\d*\.?(\d*)?\s*$/ =~ 'te1'
+
+is_number("te1")
+is_number("..2")
+is_number('+.8')
+is_number('-1.')
+is_number(".1")
+is_number("2e10")
+is_number(" -90e3   " )
+is_number(" 1e" )
+is_number(" 6e-1" )
+is_number(" 99e2.5 " )
+is_number("53.5e93" )
+is_number("95a54e53" )
+is_number("0")
+is_number(" 0.1 ")
+is_number("abc" )
+is_number("1 a" )
+is_number("e3" )
+is_number(" --6 " )
+is_number("-+3" )
+
+
+/^\.\..*$/ =~ "..2"
+
+/^\s*(?!\-\+)([+-]\d)?\d*\.?(\.\d)?\d*([e]\d)?(e[+-]\d+)?\d*\.?(\d*)?\s*$/ =~ "-1."
+/^(?!\+\.)/ =~ '+.8'

hard/median-of-two-sorted-arrays/sub.rb

@@ -0,0 +1,18 @@
+
+
+
+find combined length, if odd then we're looking for the median of the set
+if even then we're looking for the sum / 2 of the two middle numbers
+
+
+
+
+
+
+
+# @param {Integer[]} nums1
+# @param {Integer[]} nums2
+# @return {Float}
+def find_median_sorted_arrays(nums1, nums2)
+
+end

hard/valid_num.rb

@@ -0,0 +1,29 @@
+
+/^[+-]?\d+[\.]0$/ =~ "123.0"  # => 0
+
+/[+-]?(\d+[e?]|\d+[e?]\d*)([.]\d*)?/ =~ "123"  # => nil
+
+def is_number(s)
+
+  /^[+-]?\d+[\.]0$/ =~ s  # => nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, ...
+
+#    /[+-]?(\d+[e?]|\d+[e?]\d*)([.]\d*)?/ =~ s  # => nil, nil, nil, nil, 0, 1, 1, nil, 1, 1, ...
+end                                             # => :is_number
+
+
+is_number("2e10")        # => 0
+is_number(" -90e3   " )  # => 1
+is_number(" 1e" )        # => 1
+is_number(" 6e-1" )      # => 1
+is_number(" 99e2.5 " )   # => 1
+is_number("53.5e93" )    # => 3
+is_number("95a54e53" )   # => 3
+
+
+is_number("0")           # => nil
+is_number(" 0.1 ")       # => nil
+is_number("abc" )        # => nil
+is_number("1 a" )        # => nil
+is_number("e3" )         # => nil
+is_number(" --6 " )      # => nil
+is_number("-+3" )        # => nil

hard/valid_num.rb~

@@ -0,0 +1,3 @@
+def is_number(s)
+    /[+-]?(\d+[e?]|\d+[e?]\d*)([.]\d*)?/ =~ s
+end

medium/939/medium_area_rectangle.py

@@ -0,0 +1,19 @@
+class Solution(object):
+    def minAreaRect(self, points):
+        columns = collections.defaultdict(list)
+        for x, y in points:
+            columns[x].append(y)
+        lastx = {}
+        ans = float('inf')
+        for x in sorted(columns):
+            column = columns[x]
+            column.sort()
+            for j, y2 in enumerate(column):
+                for i in range(j):
+                    y1 = column[i]
+                    if (y1, y2) in lastx:
+                        ans = min(ans, (x - lastx[y1,y2]) * (y2 - y1))
+                    lastx[y1, y2] = x
+        return ans if ans < float('inf') else 0
+
+#