Maximum Number of Operations With the Same Score II

CMakeLists.txt

@@ -845,6 +845,7 @@ add_task(maximum-number-of-fish-in-a-grid)
 add_task(maximum-number-of-non-overlapping-palindrome-substrings)
 add_task(maximum-number-of-ones)
 add_task(maximum-number-of-operations-with-the-same-score-i)
+add_task(maximum-number-of-operations-with-the-same-score-ii)
 add_task(maximum-number-of-pairs-in-array)
 add_task(maximum-number-of-points-from-grid-queries)
 add_task(maximum-number-of-removable-characters)

PROBLEM_LIST.md

@@ -1885,6 +1885,7 @@
 | 3036. | [Number of Subarrays That Match a Pattern II](https://leetcode.com/problems/number-of-subarrays-that-match-a-pattern-ii/) | [C++](./solutions/number-of-subarrays-that-match-a-pattern-ii/solution.hpp) | <img src='https://img.shields.io/badge/Hard-darkred?style=flat-square'/> | O(N+M) / O(M)| <img src='https://img.shields.io/badge/Array-57337f?style=flat-square'/> <img src='https://img.shields.io/badge/Rolling Hash-6b7f33?style=flat-square'/> <img src='https://img.shields.io/badge/String Matching-7f3346?style=flat-square'/> <img src='https://img.shields.io/badge/Hash Function-647f33?style=flat-square'/> |  |
 | 3038. | [Maximum Number of Operations With the Same Score I](https://leetcode.com/problems/maximum-number-of-operations-with-the-same-score-i/) | [C++](./solutions/maximum-number-of-operations-with-the-same-score-i/solution.hpp) | <img src='https://img.shields.io/badge/Easy-darkgreen?style=flat-square'/> | O(N) / O(1)|  |  |
 | 3039. | [Apply Operations to Make String Empty](https://leetcode.com/problems/apply-operations-to-make-string-empty/) | [C++](./solutions/apply-operations-to-make-string-empty/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(N) / O(1)|  |  |
+| 3040. | [Maximum Number of Operations With the Same Score II](https://leetcode.com/problems/maximum-number-of-operations-with-the-same-score-ii/) | [C++](./solutions/maximum-number-of-operations-with-the-same-score-ii/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(N<sup>2</sup>) / O(N<sup>2</sup>)|  |  |
 | 3042. | [Count Prefix and Suffix Pairs I](https://leetcode.com/problems/count-prefix-and-suffix-pairs-i/) | [C++](./solutions/count-prefix-and-suffix-pairs-i/solution.hpp) | <img src='https://img.shields.io/badge/Easy-darkgreen?style=flat-square'/> | O(N<sup>2</sup>K) / O(1)|  |  |
 | 3043. | [Find the Length of the Longest Common Prefix](https://leetcode.com/problems/find-the-length-of-the-longest-common-prefix/) | [C++](./solutions/find-the-length-of-the-longest-common-prefix/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(N+M) / O(N)|  |  |
 | 3044. | [Most Frequent Prime](https://leetcode.com/problems/most-frequent-prime/) | [C++](./solutions/most-frequent-prime/solution.hpp) | <img src='https://img.shields.io/badge/Medium-darkorange?style=flat-square'/> | O(N<sup>2</sup>M<sup>2</sup>K<sup>0.5</sup>) / O(1)|  |  |

solutions/maximum-number-of-operations-with-the-same-score-ii/CMakeLists.txt

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

solutions/maximum-number-of-operations-with-the-same-score-ii/solution.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <functional>
+#include <ranges>
+#include <vector>
+
+// Time: O(N^2)
+// Space: O(N^2)
+
+class Solution {
+public:
+  static int maxOperations(const std::vector<int> &nums) {
+    std::function<int(int, int, int, std::vector<std::vector<int>> *)> maxOps =
+        [&](int l, int r, int score,
+            std::vector<std::vector<int>> *memo) -> int {
+      if (r - l < 1) {
+        return 0;
+      }
+      auto &ans = (*memo)[l][r];
+      if (ans == -1) {
+        ans = 0;
+        if (nums[l] + nums[l + 1] == score) {
+          ans = std::max(ans, 1 + maxOps(l + 2, r, score, memo));
+        }
+        if (nums[r - 1] + nums[r] == score) {
+          ans = std::max(ans, 1 + maxOps(l, r - 2, score, memo));
+        }
+        if (nums[l] + nums[r] == score) {
+          ans = std::max(ans, 1 + maxOps(l + 1, r - 1, score, memo));
+        }
+      }
+      return ans;
+    };
+
+    const int n = nums.size();
+    int ans = 0;
+    std::vector memo(n, std::vector<int>(n));
+    for (auto score : {nums[0] + nums[1], nums[n - 2] + nums[n - 1],
+                       nums[0] + nums[n - 1]}) {
+      std::ranges::fill(memo, std::vector<int>(n, -1));
+      ans = std::max(ans, maxOps(0, n - 1, score, &memo));
+    }
+    return ans;
+  }
+};

solutions/maximum-number-of-operations-with-the-same-score-ii/test.cpp

@@ -0,0 +1,26 @@
+#include <catch.hpp>
+
+#include <solution.hpp>
+
+TEST_CASE("Simple") {
+  struct TestCase {
+    std::vector<int> nums;
+    int expected;
+  };
+
+  std::vector<TestCase> test_cases{
+      {
+          .nums{3, 2, 1, 2, 3, 4},
+          .expected = 3,
+      },
+      {
+          .nums{3, 2, 6, 1, 4},
+          .expected = 2,
+      },
+  };
+
+  for (const auto &[nums, expected] : test_cases) {
+    const auto actual = Solution::maxOperations(nums);
+    REQUIRE(expected == actual);
+  }
+}