Leetcode 2000 Reverse Prefix of Word
I am a developer from Nashville, TN. I specialize in the .NET tech stack. I have created many projects in Blazor WASM, Xamarin, MAUI, etc.
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I am a developer from Nashville, TN. I specialize in the .NET tech stack. I have created many projects in Blazor WASM, Xamarin, MAUI, etc.
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A series documenting my journey to improving my ability to solve LeetCode problems through YouTube videos, study plans, articles, etc. Using my own words for later reference.
Intuition Use two pointers to iterate through the string checking each adjacent character to see if it is "bad" or "good". Approach First if the string is 1 or fewer characters we know it is good so we can just return it. If that's not the case, we c...
Intuition Get the length of the subsequence (if any) and subtract it from the length of t to find out how many characters we have to append (if any) Approach Keep a count of the length of the subsequence while iterating through s and then subtract th...
Intuition Sort the array and check if the start and end of the array match. If not, increment or decrement accordingly. Approach First sort the array. Then use two pointers. One at the beginning, the other at the end. Check to see if the value at the...
Intuition Use two pointers to iterate through the string checking each adjacent character to see if it is "bad" or "good". Approach First if the string is 1 or fewer characters we know it is good so we can just return it. If that's not the case, we c...
Intuition Since both arrays are sorted, we can find the minimum common value by iterating from left to right with two pointers. Approach Initialize both pointers to 0 to start at the beginning of the array. While both pointers are within bounds of th...
Find position of ch (if any) then use two pointers to swap characters until string is reveresed from beginning to index of ch
Start by checking each character for ch. If we find it, that's where our right pointer will start. Our left pointer will start at the beginning of the string.
While left is less than right swap characters and then decrement right, and increment left. When they meet the substring beginning at index 0 and ending at the index of ch will be reversed.
public class Solution
{
public string ReversePrefix(string word, char ch)
{
var arr = word.ToCharArray();
int left = 0;
int right = 0;
//find pos of ch if it exists
while(right < arr.Length && arr[right] != ch)
{
right++;
}
if(right == arr.Length)
{
//if not return the original word
return word;
}
//two pointers, one at ch, the other at the start of the string
while(left < right)
{
//swap the two characters, increase the left pointer, decrease the right
var temp = arr[left];
arr[left] = arr[right];
arr[right] = temp;
left++;
right--;
}
//when both pointers meet, return
return new string(arr);
}
}