Sync LeetCode submission Runtime - 191 ms (81.29%), Memory - 19.4 MB (50.97%)

Author: jimit105

1818-maximum-score-from-removing-substrings/README.md

@@ -0,0 +1,46 @@
+<p>You are given a string <code>s</code> and two integers <code>x</code> and <code>y</code>. You can perform two types of operations any number of times.</p>
+
+<ul>
+	<li>Remove substring <code>&quot;ab&quot;</code> and gain <code>x</code> points.
+
+	<ul>
+		<li>For example, when removing <code>&quot;ab&quot;</code> from <code>&quot;c<u>ab</u>xbae&quot;</code> it becomes <code>&quot;cxbae&quot;</code>.</li>
+	</ul>
+	</li>
+	<li>Remove substring <code>&quot;ba&quot;</code> and gain <code>y</code> points.
+	<ul>
+		<li>For example, when removing <code>&quot;ba&quot;</code> from <code>&quot;cabx<u>ba</u>e&quot;</code> it becomes <code>&quot;cabxe&quot;</code>.</li>
+	</ul>
+	</li>
+</ul>
+
+<p>Return <em>the maximum points you can gain after applying the above operations on</em> <code>s</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;cdbcbbaaabab&quot;, x = 4, y = 5
+<strong>Output:</strong> 19
+<strong>Explanation:</strong>
+- Remove the &quot;ba&quot; underlined in &quot;cdbcbbaaa<u>ba</u>b&quot;. Now, s = &quot;cdbcbbaaab&quot; and 5 points are added to the score.
+- Remove the &quot;ab&quot; underlined in &quot;cdbcbbaa<u>ab</u>&quot;. Now, s = &quot;cdbcbbaa&quot; and 4 points are added to the score.
+- Remove the &quot;ba&quot; underlined in &quot;cdbcb<u>ba</u>a&quot;. Now, s = &quot;cdbcba&quot; and 5 points are added to the score.
+- Remove the &quot;ba&quot; underlined in &quot;cdbc<u>ba</u>&quot;. Now, s = &quot;cdbc&quot; and 5 points are added to the score.
+Total score = 5 + 4 + 5 + 5 = 19.</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;aabbaaxybbaabb&quot;, x = 5, y = 4
+<strong>Output:</strong> 20
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>1 &lt;= x, y &lt;= 10<sup>4</sup></code></li>
+	<li><code>s</code> consists of lowercase English letters.</li>
+</ul>

1818-maximum-score-from-removing-substrings/solution.py

@@ -0,0 +1,41 @@
+# Approach 1: Greedy Way (Stack)
+
+# Time: O(n)
+# Space: O(n)
+
+class Solution:
+    def maximumGain(self, s: str, x: int, y: int) -> int:
+        total_score = 0
+        high_priority_pair = 'ab' if x > y else 'ba'
+        low_priority_pair = 'ba' if high_priority_pair == 'ab' else 'ab'
+
+        # First pass: Remove high_priority_pair
+        string_after_first_pass = self.remove_substring(s, high_priority_pair)
+        removed_pairs_count = (len(s) - len(string_after_first_pass)) // 2
+
+        total_score += removed_pairs_count * max(x, y)
+
+        # Second pass: Remove low_priority_pair
+        string_after_second_pass = self.remove_substring(string_after_first_pass, low_priority_pair)
+        removed_pairs_count = (len(string_after_first_pass) - len(string_after_second_pass)) // 2
+
+        total_score += removed_pairs_count * min(x, y)
+
+        return total_score
+
+    def remove_substring(self, input, target_pair):
+        char_stack = []
+
+        for curr_char in input:
+            if(
+                curr_char == target_pair[1]
+                and char_stack
+                and char_stack[-1] == target_pair[0]
+            ):
+                char_stack.pop()
+            else:
+                char_stack.append(curr_char)
+
+        return ''.join(char_stack)
+
+