Create minimum-remove-to-make-valid-parentheses.cpp

Author: kamyu104

C++/minimum-remove-to-make-valid-parentheses.cpp

@@ -0,0 +1,34 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    string minRemoveToMakeValid(string s) {
+        unordered_set<int> lookup;
+        int count = 0;
+        for (auto i = 0; i < s.size(); ++i) {
+            if (s[i] == '(') {
+                ++count;
+            }
+            if (s[i] == ')') {
+                if (count) {
+                    --count;
+                } else {
+                    s[i] = ' ';
+                }
+            }
+        }
+        if (count) {
+            for (auto i = s.size() - 1; i >= 0; --i) {
+                if (s[i] == '(') {
+                    s[i] = ' ';
+                    if (--count == 0) {
+                        break;
+                    }
+                }
+            }
+        }
+        s.erase(remove(s.begin(), s.end(), ' '), s.end());
+        return s;
+    }
+};