create 2002 in java

Author: Mohammed785

java/2002-maximum-product-of-the-length of-2-palindromic-subsequences.java

@@ -0,0 +1,27 @@
+class Solution {
+    public int maxProduct(String s) {
+    int[] dp = new int[4096];
+    int res = 0, mask = (1 << s.length()) - 1;
+    for (int m = 1; m <= mask; ++m)
+        dp[m] = palSize(s, m);
+    for (int m1 = mask; m1 > 0; --m1)
+        if (dp[m1] * (s.length() - dp[m1]) > res)
+            for(int m2 = mask ^ m1; m2 > 0; m2 = (m2 - 1) & (mask ^ m1))
+                res = Math.max(res, dp[m1] * dp[m2]);
+    return res;
+}
+private int palSize(String s, int mask) {
+    int p1 = 0, p2 = s.length(), res = 0;
+    while (p1 <= p2) {
+        if ((mask & (1 << p1)) == 0)
+            ++p1;
+        else if ((mask & (1 << p2)) == 0)
+            --p2;
+        else if (s.charAt(p1) != s.charAt(p2))
+            return 0;
+        else
+            res += 1 + (p1++ != p2-- ? 1 : 0);
+    }
+    return res;
+}
+}