solves #2696: Minimum string length after removing substrings

Author: anishLearnsToCode

src/MinimumStringLengthAfterRemovingSubstrings.java

@@ -0,0 +1,31 @@
+// https://leetcode.com/problems/minimum-string-length-after-removing-substrings
+// T: O(N)
+// S: O(N)
+
+import java.util.Set;
+import java.util.Stack;
+
+public class MinimumStringLengthAfterRemovingSubstrings {
+    final static Set<Character> REMOVAL_TERMINATING_CHARS = Set.of('B', 'D');
+
+    public int minLength(String s) {
+        final Stack<Character> stack = new Stack<>();
+        for (int i = 0 ; i < s.length() ; i++) {
+            final char letter = s.charAt(i);
+            if (!stack.isEmpty() && REMOVAL_TERMINATING_CHARS.contains(letter) && stack.peek() == inverse(letter)) {
+                stack.pop();
+            } else {
+                stack.push(letter);
+            }
+        }
+        return stack.size();
+    }
+
+    private char inverse(char letter) {
+        return switch (letter) {
+            case 'B' -> 'A';
+            case 'D' -> 'C';
+            default -> ' ';
+        };
+    }
+}