add word break ii

tg123 · tg123 · commit b54655695f0b · 2014-08-28T22:21:44.000+08:00
diff --git a/word-break-ii/README.md b/word-break-ii/README.md
@@ -1,4 +1,39 @@
+## [Word Break](../word-break) with traceback
+
+In order to output all solutions, 
+just change P from `boolean` to a collection which contains all parent index.
+
+
+```
+ 0 1 2 3 4 5 6 7 8 9 A
+ * c a t s a n d d o g
+ 
+       0 0     3     7
+               4
+
+
+P[3] = [0]
+P[4] = [0]
+
+P[7] = [3, 4]
+P[10] = [7]
+
+```
+
+## Recover strings using DFS
+
+To find all strings break at breakpoint, just using DFS to find out them.
+
+ * 10, 7, 3, 0: dog sand cat
+ * 10, 7, 4, 0: dog and cats
+
+### Note:
+
+offsets here is 1 larger than the original offset.
+
+So, `7..10` here is to start form the next element, the 8th to the 11th(exclusive).
+
+Luckily, restore the `S[8th..11th]` is just the same as `S[7..10]`,
+Because index of S starts from `0`.
 
-## TODO 
-  * write down thinking
 
