cpp: add «1249. Minimum Remove to Make Valid Parentheses»

Signed-off-by: Matej Focko <mfocko@redhat.com>

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

@@ -0,0 +1,96 @@
+#include <string>
+
+class Solution {
+  public:
+    std::string minRemoveToMakeValid(std::string s) {
+        int open = 0;
+
+        for (auto i = 0u; i < s.size(); ++i) {
+            switch (s[i]) {
+            case '(':
+                // opening
+                ++open;
+                break;
+            case ')':
+                if (open > 0) {
+                    // can close
+                    --open;
+                } else {
+                    // have to remove the closing paren
+                    s.erase(i, 1);
+                    --i;
+                }
+            }
+        }
+
+        // Remove the opening brackets from end
+        for (auto i = s.size(); open > 0 && i-- > 0;) {
+            if (s[i] == '(') {
+                s.erase(i, 1);
+                --open;
+            }
+        }
+
+        return s;
+    }
+};
+
+#ifdef _MF_TEST
+#include <gtest/gtest.h>
+
+namespace {
+bool valid(const std::string &s) {
+    int open = 0;
+
+    for (char c : s) {
+        switch (c) {
+        case '(':
+            ++open;
+            break;
+        case ')':
+            if (open-- <= 0) {
+                return false;
+            }
+            break;
+        }
+    }
+
+    return open == 0;
+}
+} // namespace
+
+TEST(valid, valid_strings) {
+    EXPECT_TRUE(valid(""));
+    EXPECT_TRUE(valid("(lee(t(c)o)de)"));
+    EXPECT_TRUE(valid("lee(t(c)o)de"));
+    EXPECT_TRUE(valid("(a)b(c)d"));
+    EXPECT_TRUE(valid("ab(c)d"));
+    EXPECT_TRUE(valid("(())(())"));
+}
+
+TEST(valid, invalid_strings) {
+    EXPECT_FALSE(valid("lee(t(c)o)de)"));
+    EXPECT_FALSE(valid("a)b(c)d"));
+    EXPECT_FALSE(valid("))(("));
+}
+
+TEST(examples, _1) {
+    Solution s;
+    EXPECT_TRUE(valid(s.minRemoveToMakeValid("lee(t(c)o)de)")));
+}
+
+TEST(examples, _2) {
+    Solution s;
+    EXPECT_TRUE(valid(s.minRemoveToMakeValid("a)b(c)d")));
+}
+
+TEST(examples, _3) {
+    Solution s;
+    EXPECT_TRUE(valid(s.minRemoveToMakeValid("))((")));
+}
+
+int main(int argc, char **argv) {
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
+#endif