Sync LeetCode submission Runtime - 220 ms (77.73%), Memory - 62.5 MB (13.54%)

Author: jimit105

3647-zero-array-transformation-iii/README.md

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+<p>You are given an integer array <code>nums</code> of length <code>n</code> and a 2D array <code>queries</code> where <code>queries[i] = [l<sub>i</sub>, r<sub>i</sub>]</code>.</p>
+
+<p>Each <code>queries[i]</code> represents the following action on <code>nums</code>:</p>
+
+<ul>
+	<li>Decrement the value at each index in the range <code>[l<sub>i</sub>, r<sub>i</sub>]</code> in <code>nums</code> by <strong>at most</strong><strong> </strong>1.</li>
+	<li>The amount by which the value is decremented can be chosen <strong>independently</strong> for each index.</li>
+</ul>
+
+<p>A <strong>Zero Array</strong> is an array with all its elements equal to 0.</p>
+
+<p>Return the <strong>maximum </strong>number of elements that can be removed from <code>queries</code>, such that <code>nums</code> can still be converted to a <strong>zero array</strong> using the <em>remaining</em> queries. If it is not possible to convert <code>nums</code> to a <strong>zero array</strong>, return -1.</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 = [2,0,2], queries = [[0,2],[0,2],[1,1]]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">1</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<p>After removing <code>queries[2]</code>, <code>nums</code> can still be converted to a zero array.</p>
+
+<ul>
+	<li>Using <code>queries[0]</code>, decrement <code>nums[0]</code> and <code>nums[2]</code> by 1 and <code>nums[1]</code> by 0.</li>
+	<li>Using <code>queries[1]</code>, decrement <code>nums[0]</code> and <code>nums[2]</code> by 1 and <code>nums[1]</code> by 0.</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [1,1,1,1], queries = [[1,3],[0,2],[1,3],[1,2]]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">2</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<p>We can remove <code>queries[2]</code> and <code>queries[3]</code>.</p>
+</div>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [1,2,3,4], queries = [[0,3]]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">-1</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<p><code>nums</code> cannot be converted to a zero array even after using all the queries.</p>
+</div>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>0 &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
+	<li><code>1 &lt;= queries.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>queries[i].length == 2</code></li>
+	<li><code>0 &lt;= l<sub>i</sub> &lt;= r<sub>i</sub> &lt; nums.length</code></li>
+</ul>

3647-zero-array-transformation-iii/solution.py

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+# Approach: Greedy + Priority Queue
+
+class Solution:
+    def maxRemoval(self, nums: List[int], queries: List[List[int]]) -> int:
+        queries.sort(key=lambda x: x[0])
+        heap = []
+        delta_array = [0] * (len(nums) + 1)
+        operations = 0
+        j = 0
+
+        for i, num in enumerate(nums):
+            operations += delta_array[i]
+            while j < len(queries) and queries[j][0] == i:
+                heapq.heappush(heap, -queries[j][1])
+                j += 1
+            while operations < num and heap and -heap[0] >= i:
+                operations += 1
+                delta_array[-heappop(heap) + 1] -= 1
+            if operations < num:
+                return -1
+        
+        return len(heap)
+