create 2002 in rust

Author: Mohammed785

rust/2002-maximum-product-of-the-length-of-two-palindromic-subsequences.rs

@@ -0,0 +1,55 @@
+impl Solution {
+    pub fn max_product(s: String) -> i32 {
+        let s: Vec<char> = s.chars().collect();
+        let mut s1 = vec![];
+        let mut s2 = vec![];
+        let mut res = 0;
+
+        Solution::dfs(&s, &mut s1, &mut s2, &mut res, 0);
+
+        res
+    }
+
+    fn dfs(s: &[char], s1: &mut Vec<char>, s2: &mut Vec<char>, res: &mut i32, index: usize) {
+        // Base case
+        if index == s.len() {
+            if Solution::is_palindrome(s1) && Solution::is_palindrome(s2) {
+                let new_max = s1.len() * s2.len();
+                *res = std::cmp::max(*res, new_max as i32);
+            }
+            return;
+        }
+
+        // Option 0: Not in S1 nor S2
+        Solution::dfs(s, s1, s2, res, index + 1);
+
+        // Option 1: in S1
+        s1.push(s[index]);
+        Solution::dfs(s, s1, s2, res, index + 1);
+        s1.pop();
+
+        // Option 2: in S2
+        s2.push(s[index]);
+        Solution::dfs(s, s1, s2, res, index + 1);
+        s2.pop();
+    }
+
+    fn is_palindrome(s: &[char]) -> bool {
+        if s.len() <= 1 {
+            return true;
+        }
+
+        let mut l = 0;
+        let mut r = s.len() - 1;
+
+        while l < r {
+            if s[l] != s[r] {
+                return false;
+            }
+            l += 1;
+            r -= 1;
+        }
+
+        true
+    }
+}