no message

Author: wuduhren

problems/text-justification.py

@@ -0,0 +1,68 @@
+"""
+The description of this problem is unclear.
+"Extra spaces between words should be distributed as evenly as possible." Should be "Extra spaces between words IN EACH LINE should be distributed as evenly as possible."
+So the problem in short is:
+1. Every line should have as many as word as possible. But they should be separate by space or spaces.
+2. Mid align all the line. Except the last line and the lines with one word.
+3. For mid align, distribute space evenly, if there are extra spaces, it should be located left. For example 5 spaces distribute to 2 places, it should be 3 2, not 2 3. 7 spaces distribute to 3 places, it should be 3 2 2, not 2 3 2, not 2 2 3.
+
+Time: O(N), N is the number of words.
+Space: O(W), W is maxWidth for keeping strings in currLine. Can further reduce to O(1) using only index.
+"""
+class Solution(object):
+    def fullJustify(self, words, maxWidth):
+        def canAddToCurrLine(word, currLineStringLength):
+            currWidth = len(currLine)-1 + currLineStringLength # space+currLineStringLength
+            return currWidth+len(word)+1<=maxWidth
+        
+        def leftAlign(currLine):
+            line = ''
+            
+            for word in currLine:
+                line += word + ' '
+            line = line[:-1] #remove last space
+            
+            line += ' '*(maxWidth-len(line))
+            return line
+        
+        def midAlign(currLine, currLineStringLength):
+            line = ''
+            
+            totalSpaceCount = maxWidth-currLineStringLength
+            extraSpaceCount = totalSpaceCount%(len(currLine)-1)
+            spaceCount = totalSpaceCount-extraSpaceCount
+            spaces = ' '*(totalSpaceCount/(len(currLine)-1))
+            
+            for word in currLine:
+                line += word
+                if spaceCount>0:
+                    line += spaces
+                    spaceCount -= len(spaces)
+                
+                if extraSpaceCount>0:
+                    line += ' '
+                    extraSpaceCount -= 1
+                    
+            return line
+            
+        currLineStringLength = 0
+        currLine = []
+        ans = []
+        
+        i = 0
+        while i<len(words):
+            if canAddToCurrLine(words[i], currLineStringLength):
+                currLine.append(words[i])
+                currLineStringLength += len(words[i])
+                i += 1
+            else:
+                if len(currLine)==1:
+                    ans.append(leftAlign(currLine)) #line with one word align left
+                else:
+                    ans.append(midAlign(currLine, currLineStringLength))
+                
+                currLine = []
+                currLineStringLength = 0
+                
+        ans.append(leftAlign(currLine)) #last line should always align left
+        return ans