Apartments

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

// Sorting. Just used https://www.geeksforgeeks.org/c/qsort-function-in-c/
int comp(const void *a, const void *b) {
    int x = *(const int *)a;
    int y = *(const int *)b;

    if (x < y)
        return -1;
    if (x > y)
        return 1;
    return 0;
}

int main(){
    // INITIALIZATION

    int applicantNum, apartmentNum, maxDiff;
    
    if (scanf("%i %i %i", &applicantNum, &apartmentNum, &maxDiff) != 3){
        return 0;
    }

    int* applicants = (int*)malloc(applicantNum * sizeof(int));
    // Read applicant wishes
    for (int i = 0; i < applicantNum; i++) {
        if (scanf("%d", &applicants[i]) != 1){
            return 0;
        }
    }

    int* apartments = (int*)malloc(apartmentNum * sizeof(int));
    // Read apartment sizes
    for (int i = 0; i < apartmentNum; i++) {
        if (scanf("%d", &apartments[i]) != 1){
            return 0;
        }
    }

    // MAIN PROGRAM

    // We want to find as many apartments for as many people as we can.
    // Lets fill them up from the bottom. (Smallest first)

    // Sort smallest first.
    qsort(applicants, applicantNum, sizeof(int), comp);
    qsort(apartments, apartmentNum, sizeof(int), comp);

    int found = 0;
    unsigned int current_hus = 0;

    for (unsigned int man = 0; man < applicantNum; man++)
    {
        // We dont want to give away apartments, that we have already given to best candidate.
        for (unsigned int hus = current_hus; hus < apartmentNum; hus++)
        {
            if (// If apartment is bigger than what we wish for...
                apartments[hus] >= (applicants[man] - maxDiff)
                // But smaller than we dont want.
                && apartments[hus] <= (applicants[man] + maxDiff))
            {
                found++;
                current_hus = hus + 1;
                break;
            }
            // Check ceiling, if it doesnt fit, no more looping.
            if (apartments[hus] > (applicants[man] + maxDiff)) {
                break;
            }
        }   
    }
    
    // OUTPUT

    printf("%i", found);

    free(applicants);
    free(apartments);

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED