Find the Student that Will Replace the Chalk

Leetcode Problem:

• Find the Student that Will Replace the Chalk

Summary

• Find the index of the student who will replace the chalk pieces

Approach

• The solution uses the modulo operator to find the remaining chalk pieces after each student's turn
• It then iterates through the chalk array to find the student who will run out of chalk first.

Complexity

• O(n) where n is the number of students

Explain

• The solution works by first calculating the total amount of chalk available
• It then uses the modulo operator to find the remaining chalk pieces after each student's turn
• The student who will run out of chalk first is the one whose index is returned
• This approach ensures that the student who will replace the chalk is found efficiently, even for large inputs.

Solution Code:

class Solution {
public:
    int chalkReplacer(vector& chalk, int k) {
        long long sum = 0;
        for(int i = 0 ; i < chalk.size(); i++){
            sum += chalk[i];
        }
        k = k % sum;
        for(int i = 0 ; i < chalk.size(); i++){
            k -= chalk[i];
            if (k < 0) return i;
        }
        return 0;
    }
};