Minimum Length of String After Deleting Similar Ends

CMakeLists.txt

@@ -966,6 +966,7 @@ add_task(minimum-index-sum-of-two-lists)
 add_task(minimum-insertion-steps-to-make-a-string-palindrome)
 add_task(minimum-jumps-to-reach-home)
 add_task(minimum-knight-moves)
+add_task(minimum-length-of-string-after-deleting-similar-ends)
 add_task(minimum-limit-of-balls-in-a-bag)
 add_task(minimum-moves-to-capture-the-queen)
 add_task(minimum-moves-to-convert-string)

PROBLEM_LIST.md

@@ -1230,6 +1230,7 @@
 | 1745. | [Palindrome Partitioning IV](https://leetcode.com/problems/palindrome-partitioning-iv/) | [C++](./solutions/palindrome-partitioning-iv/solution.hpp) | <img src='https://img.shields.io/badge/Hard-darkred?style=flat-square'/> | O(N<sup>2</sup>) / O(N)| <img src='https://img.shields.io/badge/String-7f334c?style=flat-square'/> <img src='https://img.shields.io/badge/Dynamic Programming-37337f?style=flat-square'/> |  |
 | 1747. | [Leetflex Banned Accounts 🔒](https://leetcode.com/problems/leetflex-banned-accounts/) | [SQL](./extra/sql/leetflex-banned-accounts/solution.sql), [PY](./extra/pandas/leetflex-banned-accounts/solution.py) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | | <img src='https://img.shields.io/badge/Database-337c7f?style=flat-square'/> |  |
 | 1748. | [Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/) | [C++](./solutions/sum-of-unique-elements/solution.hpp) | <img src='https://img.shields.io/badge/Easy-darkgreen?style=flat-square'/> | | <img src='https://img.shields.io/badge/Array-57337f?style=flat-square'/> <img src='https://img.shields.io/badge/Hash Table-7f337a?style=flat-square'/> <img src='https://img.shields.io/badge/Counting-7f7333?style=flat-square'/> |  |
+| 1750. | [Minimum Length of String After Deleting Similar Ends](https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends/) | [C++](./solutions/minimum-length-of-string-after-deleting-similar-ends/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(N) / O(1)| <img src='https://img.shields.io/badge/Two Pointers-7f6633?style=flat-square'/> <img src='https://img.shields.io/badge/String-7f334c?style=flat-square'/> |  |
 | 1751. | [Maximum Number of Events That Can Be Attended II](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended-ii/) | [C++](./solutions/maximum-number-of-events-that-can-be-attended-ii/solution.hpp) | <img src='https://img.shields.io/badge/Hard-darkred?style=flat-square'/> | | <img src='https://img.shields.io/badge/Array-57337f?style=flat-square'/> <img src='https://img.shields.io/badge/Binary Search-33557f?style=flat-square'/> <img src='https://img.shields.io/badge/Dynamic Programming-37337f?style=flat-square'/> <img src='https://img.shields.io/badge/Sorting-333b7f?style=flat-square'/> |  |
 | 1752. | [Check if Array Is Sorted and Rotated](https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/) | [C++](./solutions/check-if-array-is-sorted-and-rotated/solution.hpp) | <img src='https://img.shields.io/badge/Easy-darkgreen?style=flat-square'/> | | <img src='https://img.shields.io/badge/Array-57337f?style=flat-square'/> |  |
 | 1753. | [Maximum Score From Removing Stones](https://leetcode.com/problems/maximum-score-from-removing-stones/) | [C++](./solutions/maximum-score-from-removing-stones/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(1) / O(1)| <img src='https://img.shields.io/badge/Math-7f5933?style=flat-square'/> <img src='https://img.shields.io/badge/Greedy-44337f?style=flat-square'/> <img src='https://img.shields.io/badge/Heap (Priority Queue)-71337f?style=flat-square'/> |  |

solutions/minimum-length-of-string-after-deleting-similar-ends/CMakeLists.txt

@@ -0,0 +1 @@
+add_catch(test_minimum_length_of_string_after_deleting_similar_ends test.cpp)

solutions/minimum-length-of-string-after-deleting-similar-ends/solution.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <string>
+
+// Time: O(N)
+// Space: O(1)
+
+class Solution {
+public:
+  static int minimumLength(std::string s) {
+    int l = 0, r = s.size() - 1;
+    while (l < r && s[l] == s[r]) {
+      const auto c = s[l];
+      while (l <= r && s[l] == c) {
+        ++l;
+      }
+      while (l <= r && s[r] == c) {
+        --r;
+      }
+    }
+    return r - l + 1;
+  }
+};

solutions/minimum-length-of-string-after-deleting-similar-ends/test.cpp

@@ -0,0 +1,30 @@
+#include <catch.hpp>
+
+#include <solution.hpp>
+
+TEST_CASE("Simple") {
+  struct TestCase {
+    std::string s;
+    int expected;
+  };
+
+  std::vector<TestCase> test_cases{
+      {
+          .s = "ca",
+          .expected = 2,
+      },
+      {
+          .s = "cabaabac",
+          .expected = 0,
+      },
+      {
+          .s = "aabccabba",
+          .expected = 3,
+      },
+  };
+
+  for (const auto &[s, expected] : test_cases) {
+    const auto actual = Solution::minimumLength(s);
+    REQUIRE(expected == actual);
+  }
+}