Create 0139-word-break.kt

kotlin/0139-word-break.kt

@@ -0,0 +1,17 @@
+class Solution {
+ fun wordBreak(s: String, wordDict: List<String>): Boolean {
+ val cache = BooleanArray(s.length+1)
+ cache[s.length] = true // lastPos is true, meaning [array of word length], lastPos] since string "" can be segmented of any list of any words (our dp basecase)
+ for(i in s.length-1 downTo 0){
+ for(word in wordDict){
+ if(word.length+i <= s.length){//enough chars in s for this word to be viable ?
+ if(word == s.substring(i, i+word.length)){// its the same word char by char?
+ if(cache[i+word.length] == true) //this cache index is true only if the cache at index [i+word.length is true]
+ cache[i] = true
+ }
+ }
+ }
+ }
+ return cache[0]
+ }
+}