Runtime: 42 ms (Top 72.6%) | Memory: 44.48 MB (Top 39.7%)

Author: AnasImloul

scripts/algorithms/R/Remove Invalid Parentheses/Remove Invalid Parentheses.java

@@ -0,0 +1,48 @@
+// Runtime: 42 ms (Top 72.6%) | Memory: 44.48 MB (Top 39.7%)
+
+class Solution {
+    public List<String> removeInvalidParentheses(String s) {
+        List<String> ans=new ArrayList<>();
+        HashSet<String> set=new HashSet<String>();
+        
+        int minBracket=removeBracket(s);
+        getAns(s, minBracket,set,ans);
+        
+        return ans;
+    }
+    
+    public void getAns(String s, int minBracket, HashSet<String> set, List<String> ans){
+        if(set.contains(s)) return;
+        
+        set.add(s);
+        
+        if(minBracket==0){
+            int remove=removeBracket(s);   
+            if(remove==0) ans.add(s);
+            return;
+        }
+        
+        for(int i=0;i<s.length();i++){
+            if(s.charAt(i)!='(' && s.charAt(i)!=')') continue;
+            String L=s.substring(0,i);
+            String R=s.substring(i+1);
+            
+            if(!set.contains(L+R)) getAns(L+R,minBracket-1,set,ans);
+        }
+    }
+    
+    public int removeBracket(String s){
+        Stack<Character> stack=new Stack<>();
+        
+        for(int i=0;i<s.length();i++){
+            char x=s.charAt(i);
+            
+            if(x=='(') stack.push(x);
+            else if(x==')'){
+                if(!stack.isEmpty() && stack.peek()=='(') stack.pop();
+                else stack.push(x);
+            } 
+        }
+        return stack.size();
+    }
+}