Sync LeetCode submission Runtime - 509 ms (46.56%), Memory - 20.5 MB (82.06%)

Author: jimit105

2520-using-a-robot-to-print-the-lexicographically-smallest-string/README.md

@@ -0,0 +1,51 @@
+<p>You are given a string <code>s</code> and a robot that currently holds an empty string <code>t</code>. Apply one of the following operations until <code>s</code> and <code>t</code> <strong>are both empty</strong>:</p>
+
+<ul>
+	<li>Remove the <strong>first</strong> character of a string <code>s</code> and give it to the robot. The robot will append this character to the string <code>t</code>.</li>
+	<li>Remove the <strong>last</strong> character of a string <code>t</code> and give it to the robot. The robot will write this character on paper.</li>
+</ul>
+
+<p>Return <em>the lexicographically smallest string that can be written on the paper.</em></p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;zza&quot;
+<strong>Output:</strong> &quot;azz&quot;
+<strong>Explanation:</strong> Let p denote the written string.
+Initially p=&quot;&quot;, s=&quot;zza&quot;, t=&quot;&quot;.
+Perform first operation three times p=&quot;&quot;, s=&quot;&quot;, t=&quot;zza&quot;.
+Perform second operation three times p=&quot;azz&quot;, s=&quot;&quot;, t=&quot;&quot;.
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;bac&quot;
+<strong>Output:</strong> &quot;abc&quot;
+<strong>Explanation:</strong> Let p denote the written string.
+Perform first operation twice p=&quot;&quot;, s=&quot;c&quot;, t=&quot;ba&quot;. 
+Perform second operation twice p=&quot;ab&quot;, s=&quot;c&quot;, t=&quot;&quot;. 
+Perform first operation p=&quot;ab&quot;, s=&quot;&quot;, t=&quot;c&quot;. 
+Perform second operation p=&quot;abc&quot;, s=&quot;&quot;, t=&quot;&quot;.
+</pre>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;bdda&quot;
+<strong>Output:</strong> &quot;addb&quot;
+<strong>Explanation:</strong> Let p denote the written string.
+Initially p=&quot;&quot;, s=&quot;bdda&quot;, t=&quot;&quot;.
+Perform first operation four times p=&quot;&quot;, s=&quot;&quot;, t=&quot;bdda&quot;.
+Perform second operation four times p=&quot;addb&quot;, s=&quot;&quot;, t=&quot;&quot;.
+</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>s</code> consists of only English lowercase letters.</li>
+</ul>

2520-using-a-robot-to-print-the-lexicographically-smallest-string/solution.py

@@ -0,0 +1,27 @@
+# Approach: Greedy + Stack
+
+# Z = size of character set, n = len(s)
+# Time: O(n + Z)
+# Space: O(n)
+
+from collections import Counter
+
+class Solution:
+    def robotWithString(self, s: str) -> str:
+        cnt = Counter(s)
+        stack = []
+        res = []
+        minChar = 'a'
+
+        for c in s:
+            stack.append(c)
+            cnt[c] -= 1
+            while minChar != 'z' and cnt[minChar] == 0:
+                minChar = chr(ord(minChar) + 1)
+
+            while stack and stack[-1] <= minChar:
+                res.append(stack.pop())
+
+        return ''.join(res)
+
+