1239

Author: rising0raj

1239. Maximum Length of a Concatenated String with Unique Characters.java

@@ -0,0 +1,39 @@
+// Runtime   1ms
+// Beats     100.00%
+
+
+// Memory    41.39MB
+// Beats     93.04%
+
+
+class Solution {
+    public int maxLength(List<String> arr) {
+       List<Integer> arr2 = new ArrayList<>();
+        for(String word: arr) {
+            int bitSet = str2BitInt4(word);
+            if (bitSet > 0) arr2.add(str2BitInt4(word));
+        }
+        int[] data = new int[arr2.size()];
+        for (int i = 0; i < data.length; i++)
+            data[i] = arr2.get(i);
+
+        return helper_dfs(data, 0, 0);
+    }
+    private int helper_dfs(int[] data, int begin, int bitSet) {
+        int maxLen = Integer.bitCount(bitSet);
+        for (int i = begin; i < data.length; i++) {
+            if ((data[i] | bitSet) == (data[i] ^ bitSet))
+                maxLen = Math.max(maxLen, helper_dfs(data, i + 1, bitSet | data[i]));
+        }
+        return maxLen;
+    }
+
+    private int str2BitInt4(String word){
+        int x = 0;
+        for(char c : word.toCharArray()) {
+            if ((x >> (c - 'a') & 1) == 1) return -1;
+            x |= 1 << c - 'a';
+        }
+        return x;  
+    }
+}