Arrays and strings in C#
Practice this questionWANT TO UNDERSTAND THE CONCEPT FIRST?Learn Arrays and strings in C#
Problems to practice
- Two Sum
- Best Time to Buy and Sell Stock
- Move Zeroes
- Product of Array Except Self
- Valid Palindrome
- Longest Substring Without Repeating Characters
- Group Anagrams
Example: two sum
public int[] TwoSum(int[] nums, int target) {
var map = new Dictionary<int, int>();
for (int i = 0; i < nums.Length; i++) {
int needed = target - nums[i];
if (map.ContainsKey(needed)) {
return new[] { map[needed], i };
}
map[nums[i]] = i;
}
return Array.Empty<int>();
}Time and space complexity
- Time: O(n)
- Space: O(n)
Adapted from 17_DSA_DOTNET.md · “2. Arrays and strings in C#”. Code examples are study fragments. Difficulty and core labels are editorial estimates; version-specific behavior should be checked against your project.