Word Break

Author: forest000014

word-break/forest000014.java

@@ -0,0 +1,33 @@
+/*
+
+Time Complexity: O(s * L^2)
+    - L is max length of wordDict[i]
+Space Complexity: O(s + w * L)
+*/
+class Solution {
+    public boolean wordBreak(String s, List<String> wordDict) {
+        Set<String> wordSet = new HashSet<>();
+        int maxLen = 0;
+        for (String word : wordDict) {
+            wordSet.add(word);
+            maxLen = Math.max(maxLen, word.length());
+        }
+
+        boolean[] dp = new boolean[s.length() + 1];
+        dp[0] = true;
+
+        for (int i = 0; i < s.length(); i++) {
+            for (int j = 1; j <= maxLen; j++) {
+                int beginIdx = i - j + 1;
+                if (beginIdx < 0)
+                    continue;
+                if (wordSet.contains(s.substring(beginIdx, i + 1)) && dp[beginIdx]) {
+                    dp[i + 1] = true;
+                    break;
+                }
+            }
+        }
+
+        return dp[s.length()];
+    }
+}