Create check-if-a-parentheses-string-can-be-valid.cpp

Author: kamyu104

C++/check-if-a-parentheses-string-can-be-valid.cpp

@@ -0,0 +1,26 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    bool canBeValid(string s, string locked) {
+        auto check = [&s, &locked](char c) {
+            const int begin = (c == '(') ? 0 : size(s) - 1;
+            const int end = (c == '(') ? size(s) : -1;
+            const int d = (c == '(') ? 1 : -1;
+            for (int i = begin, cnt = 0, bal = 0; i != end; i += d) {
+                if (locked[i] == '0') {
+                    ++cnt;
+                } else {
+                    bal += (s[i] == c) ? 1 : -1;
+                    if (cnt + bal < 0) {
+                        return false;
+                    }
+                }
+            }
+            return true;
+        };
+
+        return size(s) % 2 == 0 && check('(') && check(')');
+    }
+};