Learn: Linear search
What: check the items one by one until you find the target.
Cost: O(n) in the worst case, O(1) extra memory.
Use it when: the data is not sorted, is small, or you search only once. Sorting first costs O(n log n), more than one linear search.
```csharp
int[] a = { 7, 3, 9, 1 };
Console.WriteLine(Array.IndexOf(a, 9));
Console.WriteLine(Array.IndexOf(a, 5));
```
It prints 2, then -1 (not found). Array.IndexOf and List<T>.Contains are linear searches.
Read more: https://www.geeksforgeeks.org/dsa/linear-search/
#tip · TIP-033
codementor
npub1u6…v0yg2
2026-10-13 18:37:58 UTC
Author Public Key
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wss://nos.lolPublished at
2026-10-13 18:37:58 UTCEvent JSON
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"content": "Learn: Linear search\n\nWhat: check the items one by one until you find the target.\nCost: O(n) in the worst case, O(1) extra memory.\nUse it when: the data is not sorted, is small, or you search only once. Sorting first costs O(n log n), more than one linear search.\n\n```csharp\nint[] a = { 7, 3, 9, 1 };\nConsole.WriteLine(Array.IndexOf(a, 9));\nConsole.WriteLine(Array.IndexOf(a, 5));\n```\n\nIt prints 2, then -1 (not found). Array.IndexOf and List\u003cT\u003e.Contains are linear searches.\n\nRead more: https://www.geeksforgeeks.org/dsa/linear-search/\n\n#tip · TIP-033",
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