wordBreak, wordBreak.II

Author: zeroliu

src/wordBreak/wordBreak.II.java

@@ -0,0 +1,45 @@
+public class Solution {
+    public List<String> wordBreak(String s, Set<String> dict) {
+        List<String> results = new LinkedList<String>();
+        if (dict.size() == 0 || s.length() == 0) { return results; }
+        int sl = s.length();
+        ArrayList<LinkedList<Integer>> dp = new ArrayList<LinkedList<Integer>>(sl);
+        for (int i=0; i<sl; i++) {
+            dp.add(null);
+        }
+        for (int i=sl-1; i>=0; i--) {
+            for (int j=i+1; j<=sl; j++) {
+                if (dict.contains(s.substring(i, j))) {
+                    if (j == sl || dp.get(j) != null) {
+                        if (dp.get(i) == null) {
+                            dp.set(i, new LinkedList<Integer>());
+                        }
+                        dp.get(i).add(j); 
+                    }
+                }
+            }
+        }
+        if (dp.get(0) == null) {
+            return results;
+        }
+        
+        generate(s, dp, 0, new StringBuilder(), results);
+        return results;
+    }
+    
+    public void generate(String s, ArrayList<LinkedList<Integer>> dp, int index, StringBuilder sb, List<String> results) {
+        if (index == s.length()) {
+            results.add(sb.toString());
+            return;
+        }
+        LinkedList<Integer> list = dp.get(index);
+        for (int next: list) {
+            StringBuilder newSb = new StringBuilder(sb);
+            newSb.append(s.substring(index, next));
+            if (next != s.length()) {
+                newSb.append(" ");
+            }
+            generate(s, dp, next, newSb, results);
+        }
+    }
+}

src/wordBreak/wordBreak.java

@@ -0,0 +1,29 @@
+public class Solution {
+    public boolean wordBreak(String s, Set<String> dict) {
+        HashSet<String> cache = new HashSet<String>();
+        return wordBreak(s, dict, cache);
+    }
+    public boolean wordBreak(String s, Set<String> dict, HashSet<String> cache) {
+        if (cache.contains(s)) {
+            return false;
+        }
+        int sl = s.length();
+        if (sl == 0) {
+            return true;
+        }
+        StringBuilder sb = new StringBuilder();
+        for (int i=0; i<sl; i++) {
+            char c = s.charAt(i);
+            sb.append(c);
+            if (dict.contains(sb.toString())) {
+                String newStr = s.substring(i+1);
+                if (wordBreak(newStr, dict, cache)) {
+                    return true;
+                } else {
+                    cache.add(newStr);
+                }
+            }
+        }
+        return false;
+    }
+}