Minimum Operations to Reduce X to Zero

CMakeLists.txt

@@ -346,6 +346,7 @@ add_task(minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix)
 add_task(minimum-number-of-increments-on-subarrays-to-form-a-target-array)
 add_task(minimum-number-of-vertices-to-reach-all-nodes)
 add_task(minimum-one-bit-operations-to-make-integers-zero)
+add_task(minimum-operations-to-reduce-x-to-zero)
 add_task(minimum-path-sum)
 add_task(minimum-penalty-for-a-shop)
 add_task(minimum-remove-to-make-valid-parentheses)

solutions/minimum-operations-to-reduce-x-to-zero/CMakeLists.txt

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

solutions/minimum-operations-to-reduce-x-to-zero/solution.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <algorithm>
+#include <numeric>
+#include <vector>
+
+class Solution {
+public:
+  static int minOperations(const std::vector<int> &nums, int x) {
+    const auto sum = std::accumulate(nums.begin(), nums.end(), 0);
+    const auto length = maxSubArrayLen(nums, sum - x);
+    return length == -1 ? -1 : nums.size() - length;
+  }
+
+private:
+  static int maxSubArrayLen(const std::vector<int> &nums, int target_sum) {
+    const int n = nums.size();
+    int window_sum = 0;
+    int length = -1;
+    for (int l = 0, r = 0; r < n; ++r) {
+      window_sum += nums[r];
+      while (window_sum > target_sum && l <= r) {
+        window_sum -= nums[l++];
+      }
+      if (window_sum == target_sum) {
+        length = std::max(length, r - l + 1);
+      }
+    }
+    return length;
+  }
+};

solutions/minimum-operations-to-reduce-x-to-zero/test.cpp

@@ -0,0 +1,26 @@
+#include <catch.hpp>
+
+#include <solution.hpp>
+
+TEST_CASE("Simple") {
+  {
+    std::vector<int> nums{1, 1, 4, 2, 3};
+    const int x = 5;
+    REQUIRE(2 == Solution::minOperations(nums, x));
+  }
+  {
+    std::vector<int> nums{5, 6, 7, 8, 9};
+    const int x = 4;
+    REQUIRE(-1 == Solution::minOperations(nums, x));
+  }
+  {
+    std::vector<int> nums{3, 2, 20, 1, 1, 3};
+    const int x = 10;
+    REQUIRE(5 == Solution::minOperations(nums, x));
+  }
+  {
+    std::vector<int> nums{1, 2, 3, 4};
+    const int x = 10;
+    REQUIRE(4 == Solution::minOperations(nums, x));
+  }
+}