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| 1 | +## Today's 08-04-24 [Problem Link](https://leetcode.com/problems/number-of-students-unable-to-eat-lunch/description/?envType=daily-question&envId=2024-04-08) |
| 2 | +## 1700. Number of Students Unable to Eat Lunch |
| 3 | + |
| 4 | +# Intuition |
| 5 | +<!-- Describe your first thoughts on how to solve this problem. --> |
| 6 | +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. |
| 7 | + |
| 8 | +# Approach |
| 9 | +<!-- Describe your approach to solving the problem. --> |
| 10 | + |
| 11 | +**Counting Students** : |
| 12 | + - I iterated through the `students` array and count the number of students preferring each type of sandwich. |
| 13 | + - Maintained separate counters for circle and square sandwiches (`circleStudentCount` and `squareStudentCount`). |
| 14 | + |
| 15 | +**Serving Sandwiches** : |
| 16 | + - Iterated through the `sandwiches` array. |
| 17 | + - For each sandwich : |
| 18 | + - If it's a circle sandwich (`sandwich == 0`), check if there are remaining students preferring circle sandwiches (`circleStudentCount > 0`). |
| 19 | + - If yes, serve the sandwich to a circle student by decrementing `circleStudentCount`. |
| 20 | + - If no circle students left, return the count of remaining square students (`squareStudentCount`). |
| 21 | + - If it's a square sandwich (`sandwich == 1`), check if there are remaining students preferring square sandwiches (`squareStudentCount > 0`). |
| 22 | + - If yes, serve the sandwich to a square student by decrementing `squareStudentCount`. |
| 23 | + - If no square students left, returned the count of remaining circle students (`circleStudentCount`). |
| 24 | + |
| 25 | +**Return** : |
| 26 | + - If all sandwiches are served successfully, returned 0, indicating no students are left without sandwiches. |
| 27 | + |
| 28 | +--- |
| 29 | +Have a look at the code , still have any confusion then please let me know in the comments |
| 30 | +Keep Solving.:) |
| 31 | + |
| 32 | +# Complexity |
| 33 | +- Time complexity : $O(n + m)$ |
| 34 | +<!-- Add your time complexity here, e.g. $$O(n)$$ --> |
| 35 | +$n$ : number of students |
| 36 | +$m$ : number of sandwiches |
| 37 | +- Space complexity : $O(1)$ |
| 38 | +<!-- Add your space complexity here, e.g. $$O(n)$$ --> |
| 39 | + |
| 40 | +# Code |
| 41 | +``` |
| 42 | +class Solution { |
| 43 | + public int countStudents(int[] students, int[] sandwiches) { |
| 44 | + |
| 45 | + // Count of students preferring circle sandwiches |
| 46 | + int circleStudentCount = 0; |
| 47 | + // Count of students preferring square sandwiches |
| 48 | + int squareStudentCount = 0; |
| 49 | +
|
| 50 | + // Counting the number of students preferring each type of sandwich |
| 51 | + for(int student : students) { |
| 52 | + if(student == 0) { |
| 53 | + circleStudentCount++; |
| 54 | + } |
| 55 | + else { |
| 56 | + squareStudentCount++; |
| 57 | + } |
| 58 | + } |
| 59 | +
|
| 60 | + // Iterating through sandwiches and serving them to students |
| 61 | + for(int sandwich : sandwiches) { |
| 62 | +
|
| 63 | + // If the sandwich type is circle and there are no more students preferring circle sandwiches, return the count of students preferring square sandwiches |
| 64 | + if(sandwich == 0 && circleStudentCount == 0) { |
| 65 | + return squareStudentCount; |
| 66 | + } |
| 67 | + // If the sandwich type is square and there are no more students preferring square sandwiches, return the count of students preferring circle sandwiches |
| 68 | + if(sandwich == 1 && squareStudentCount == 0) { |
| 69 | + return circleStudentCount; |
| 70 | + } |
| 71 | + // If the sandwich type is circle, serve it to a circle student and decrease the count of circle students |
| 72 | + if(sandwich == 0) { |
| 73 | + circleStudentCount--; |
| 74 | + } |
| 75 | + // If the sandwich type is square, serve it to a square student and decrease the count of square students |
| 76 | + else { |
| 77 | + squareStudentCount--; |
| 78 | + } |
| 79 | + } |
| 80 | + // All sandwiches have been served without any issues |
| 81 | + return 0; |
| 82 | + } |
| 83 | +} |
| 84 | +
|
| 85 | +``` |
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