Sync LeetCode submission Runtime - 100 ms (57.26%), Memory - 257.5 MB (58.12%)

Author: koralkulacoglu

LeetCode/4190-minimum-operations-to-reach-target-array/README.md

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+<p>You are given two integer arrays <code>nums</code> and <code>target</code>, each of length <code>n</code>, where <code>nums[i]</code> is the current value at index <code>i</code> and <code>target[i]</code> is the desired value at index <code>i</code>.</p>
+
+<p>You may perform the following operation any number of times (including zero):</p>
+
+<ul>
+	<li>Choose an integer value <code>x</code></li>
+	<li>Find all <strong>maximal contiguous segments</strong> where <code>nums[i] == x</code> (a segment is <strong>maximal</strong> if it cannot be extended to the left or right while keeping all values equal to <code>x</code>)</li>
+	<li>For each such segment <code>[l, r]</code>, update <strong>simultaneously</strong>:
+	<ul>
+		<li><code>nums[l] = target[l], nums[l + 1] = target[l + 1], ..., nums[r] = target[r]</code></li>
+	</ul>
+	</li>
+</ul>
+
+<p>Return the <strong>minimum</strong> number of operations required to make <code>nums</code> equal to <code>target</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [1,2,3], target = [2,1,3]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">2</span></p>
+
+<p><strong>Explanation:</strong>​​​​​​​</p>
+
+<ul>
+	<li>Choose <code>x = 1</code>: maximal segment <code>[0, 0]</code> updated -&gt; nums becomes <code>[2, 2, 3]</code></li>
+	<li>Choose <code>x = 2</code>: maximal segment <code>[0, 1]</code> updated (<code>nums[0]</code> stays 2, <code>nums[1]</code> becomes 1) -&gt; <code>nums</code> becomes <code>[2, 1, 3]</code></li>
+	<li>Thus, 2 operations are required to convert <code>nums</code> to <code>target</code>.​​​​​​​​​​​​​​</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [4,1,4], target = [5,1,4]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">1</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li>Choose <code>x = 4</code>: maximal segments <code>[0, 0]</code> and <code>[2, 2]</code> updated (<code>nums[2]</code> stays 4) -&gt; <code>nums</code> becomes <code>[5, 1, 4]</code></li>
+	<li>Thus, 1 operation is required to convert <code>nums</code> to <code>target</code>.</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [7,3,7], target = [5,5,9]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">2</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li>Choose <code>x = 7</code>: maximal segments <code>[0, 0]</code> and <code>[2, 2]</code> updated -&gt; <code>nums</code> becomes <code>[5, 3, 9]</code></li>
+	<li>Choose <code>x = 3</code>: maximal segment <code>[1, 1]</code> updated -&gt; <code>nums</code> becomes <code>[5, 5, 9]</code></li>
+	<li>Thus, 2 operations are required to convert <code>nums</code> to <code>target</code>.</li>
+</ul>
+</div>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= n == nums.length == target.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>1 &lt;= nums[i], target[i] &lt;= 10<sup>5</sup></code></li>
+</ul>

LeetCode/4190-minimum-operations-to-reach-target-array/solution.cpp

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+class Solution {
+public:
+    int minOperations(vector<int>& nums, vector<int>& target) {
+        unordered_map<int, bool> fixed;
+        int ans = 0;
+        int n = nums.size();
+        for (int i=0; i<n; i++) {
+            if (nums[i] != target[i] && !fixed[nums[i]]) {
+                fixed[nums[i]] = true;
+                ans++;
+            }
+        }
+        return ans;
+    }
+};