15-Ab / Leetcode-Daily-Challenge

Leetcode Daily Challenge Solution

Leetcode Daily Challenge Solutions

This is my attempt to make the coding experience easier for you guys so that you can easily learn what to do in today's leetcode challenge.

Always here to assist you guys.

Today's 08-04-24 Problem Link

1700. Number of Students Unable to Eat Lunch

Intuition

The task is to count the number of students who will be unable to get a sandwich. There are two types of sandwiches, circle, and square, represented by the integers 0 and 1 respectively. Students are also represented by integers, where 0 indicates a preference for circle sandwiches and 1 indicates a preference for square sandwiches.

Approach

Counting Students :

• I iterated through the students array and count the number of students preferring each type of sandwich.
• Maintained separate counters for circle and square sandwiches (circleStudentCount and squareStudentCount).

Serving Sandwiches :

• Iterated through the sandwiches array.
• For each sandwich :
  • If it's a circle sandwich (sandwich == 0), check if there are remaining students preferring circle sandwiches (circleStudentCount > 0).
    • If yes, serve the sandwich to a circle student by decrementing circleStudentCount.
    • If no circle students left, return the count of remaining square students (squareStudentCount).
  • If it's a square sandwich (sandwich == 1), check if there are remaining students preferring square sandwiches (squareStudentCount > 0).
    • If yes, serve the sandwich to a square student by decrementing squareStudentCount.
    • If no square students left, returned the count of remaining circle students (circleStudentCount).

Return :

• If all sandwiches are served successfully, returned 0, indicating no students are left without sandwiches.

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Have a look at the code , still have any confusion then please let me know in the comments Keep Solving.:)

Complexity

• Time complexity : $O(n + m)$

$n$ : number of students $m$ : number of sandwiches

• Space complexity : $O(1)$

Code

class Solution {
    public int countStudents(int[] students, int[] sandwiches) {
        
        // Count of students preferring circle sandwiches
        int circleStudentCount = 0;
        // Count of students preferring square sandwiches
        int squareStudentCount = 0;

        // Counting the number of students preferring each type of sandwich
        for(int student : students) {
            if(student == 0) {
                circleStudentCount++;
            }
            else {
                squareStudentCount++;
            }
        }

        // Iterating through sandwiches and serving them to students
        for(int sandwich : sandwiches) {

            // If the sandwich type is circle and there are no more students preferring circle sandwiches, return the count of students preferring square sandwiches
            if(sandwich == 0 && circleStudentCount == 0) {
                return squareStudentCount;
            }
            // If the sandwich type is square and there are no more students preferring square sandwiches, return the count of students preferring circle sandwiches
            if(sandwich == 1 && squareStudentCount == 0) {
                return circleStudentCount;
            }
            // If the sandwich type is circle, serve it to a circle student and decrease the count of circle students
            if(sandwich == 0) {
                circleStudentCount--;
            }
            // If the sandwich type is square, serve it to a square student and decrease the count of square students
            else {
                squareStudentCount--;
            }
        }
        // All sandwiches have been served without any issues
        return 0;
    }
}