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Author: jimit105

2320-find-all-k-distant-indices-in-an-array/README.md

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+<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> and two integers <code>key</code> and <code>k</code>. A <strong>k-distant index</strong> is an index <code>i</code> of <code>nums</code> for which there exists at least one index <code>j</code> such that <code>|i - j| &lt;= k</code> and <code>nums[j] == key</code>.</p>
+
+<p>Return <em>a list of all k-distant indices sorted in <strong>increasing order</strong></em>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [3,4,9,1,3,9,5], key = 9, k = 1
+<strong>Output:</strong> [1,2,3,4,5,6]
+<strong>Explanation:</strong> Here, <code>nums[2] == key</code> and <code>nums[5] == key.
+- For index 0, |0 - 2| &gt; k and |0 - 5| &gt; k, so there is no j</code> where <code>|0 - j| &lt;= k</code> and <code>nums[j] == key. Thus, 0 is not a k-distant index.
+- For index 1, |1 - 2| &lt;= k and nums[2] == key, so 1 is a k-distant index.
+- For index 2, |2 - 2| &lt;= k and nums[2] == key, so 2 is a k-distant index.
+- For index 3, |3 - 2| &lt;= k and nums[2] == key, so 3 is a k-distant index.
+- For index 4, |4 - 5| &lt;= k and nums[5] == key, so 4 is a k-distant index.
+- For index 5, |5 - 5| &lt;= k and nums[5] == key, so 5 is a k-distant index.
+- For index 6, |6 - 5| &lt;= k and nums[5] == key, so 6 is a k-distant index.
+</code>Thus, we return [1,2,3,4,5,6] which is sorted in increasing order. 
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [2,2,2,2,2], key = 2, k = 2
+<strong>Output:</strong> [0,1,2,3,4]
+<strong>Explanation:</strong> For all indices i in nums, there exists some index j such that |i - j| &lt;= k and nums[j] == key, so every index is a k-distant index. 
+Hence, we return [0,1,2,3,4].
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 1000</code></li>
+	<li><code>1 &lt;= nums[i] &lt;= 1000</code></li>
+	<li><code>key</code> is an integer from the array <code>nums</code>.</li>
+	<li><code>1 &lt;= k &lt;= nums.length</code></li>
+</ul>

2320-find-all-k-distant-indices-in-an-array/solution.py

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+# Approach 2: One-time Traversal
+
+# Time: O(n)
+# Space: O(1)
+
+class Solution:
+    def findKDistantIndices(self, nums: List[int], key: int, k: int) -> List[int]:
+        res = []
+        r = 0
+        n = len(nums)
+
+        for j in range(n):
+            if nums[j] == key:
+                l = max(r, j - k)
+                r = min(n - 1, j + k) + 1
+                for i in range(l, r):
+                    res.append(i)
+
+        return res
+