Sync LeetCode submission Runtime - 87 ms (49.85%), Memory - 55.6 MB (27.67%)

Author: jimit105

3639-zero-array-transformation-i/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>For each <code>queries[i]</code>:</p>
+
+<ul>
+	<li>Select a <span data-keyword="subset">subset</span> of indices within the range <code>[l<sub>i</sub>, r<sub>i</sub>]</code> in <code>nums</code>.</li>
+	<li>Decrement the values at the selected indices by 1.</li>
+</ul>
+
+<p>A <strong>Zero Array</strong> is an array where all elements are equal to 0.</p>
+
+<p>Return <code>true</code> if it is <em>possible</em> to transform <code>nums</code> into a <strong>Zero Array </strong>after processing all the queries sequentially, otherwise return <code>false</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 = [1,0,1], queries = [[0,2]]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">true</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li><strong>For i = 0:</strong>
+
+	<ul>
+		<li>Select the subset of indices as <code>[0, 2]</code> and decrement the values at these indices by 1.</li>
+		<li>The array will become <code>[0, 0, 0]</code>, which is a Zero Array.</li>
+	</ul>
+	</li>
+</ul>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">nums = [4,3,2,1], queries = [[1,3],[0,2]]</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">false</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<ul>
+	<li><strong>For i = 0:</strong>
+
+	<ul>
+		<li>Select the subset of indices as <code>[1, 2, 3]</code> and decrement the values at these indices by 1.</li>
+		<li>The array will become <code>[4, 2, 1, 0]</code>.</li>
+	</ul>
+	</li>
+	<li><strong>For i = 1:</strong>
+	<ul>
+		<li>Select the subset of indices as <code>[0, 1, 2]</code> and decrement the values at these indices by 1.</li>
+		<li>The array will become <code>[3, 1, 0, 0]</code>, which is not a Zero Array.</li>
+	</ul>
+	</li>
+</ul>
+</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>

3639-zero-array-transformation-i/solution.py

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+# Approach: Difference Array
+
+# n = len(nums), m = len(queries)
+# Time: O(n + m)
+# Space: O(n)
+
+class Solution:
+    def isZeroArray(self, nums: List[int], queries: List[List[int]]) -> bool:
+        delta_array = [0] * (len(nums) + 1)
+        for left, right in queries:
+            delta_array[left] += 1
+            delta_array[right + 1] -= 1
+
+        operation_count = []
+        curr_operations = 0
+
+        for delta in delta_array:
+            curr_operations += delta
+            operation_count.append(curr_operations)
+
+        for operations, target in zip(operation_count, nums):
+            if operations < target:
+                return False
+
+        return True
+