Apple and Orange

https://www.hackerrank.com/challenges/apple-and-orange/problem

#include <assert.h>
#include <limits.h>
#include <math.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* readline();
char** split_string(char*);

// Complete the countApplesAndOranges function below.
void countApplesAndOranges(int s, int t, int a, int b, int apples_count, int* apples, int oranges_count, int* oranges) {
    for(int i=0;i<apples_count;i++){
        apples[i] += a;
    }
    for(int i=0;i<oranges_count;i++){
        oranges[i] +=b;
    }
    int apple =0, orange=0;
    for(int i=0;i<apples_count;i++){
        if(apples[i]>=s && apples[i]<=t)    apple+=1;
    }
    for(int i=0;i<oranges_count;i++){
        if(oranges[i]>=s && oranges[i]<=t)    orange+=1;
    }
    printf("%d\n",apple);
    printf("%d",orange);
}

int main()
{
    char** st = split_string(readline());

    char* s_endptr;
    char* s_str = st[0];
    int s = strtol(s_str, &s_endptr, 10);

    if (s_endptr == s_str || *s_endptr != '\0') { exit(EXIT_FAILURE); }

    char* t_endptr;
    char* t_str = st[1];
    int t = strtol(t_str, &t_endptr, 10);

    if (t_endptr == t_str || *t_endptr != '\0') { exit(EXIT_FAILURE); }

    char** ab = split_string(readline());

    char* a_endptr;
    char* a_str = ab[0];
    int a = strtol(a_str, &a_endptr, 10);

    if (a_endptr == a_str || *a_endptr != '\0') { exit(EXIT_FAILURE); }

    char* b_endptr;
    char* b_str = ab[1];
    int b = strtol(b_str, &b_endptr, 10);

    if (b_endptr == b_str || *b_endptr != '\0') { exit(EXIT_FAILURE); }

    char** mn = split_string(readline());

    char* m_endptr;
    char* m_str = mn[0];
    int m = strtol(m_str, &m_endptr, 10);

    if (m_endptr == m_str || *m_endptr != '\0') { exit(EXIT_FAILURE); }

    char* n_endptr;
    char* n_str = mn[1];
    int n = strtol(n_str, &n_endptr, 10);

    if (n_endptr == n_str || *n_endptr != '\0') { exit(EXIT_FAILURE); }

    char** apples_temp = split_string(readline());

    int* apples = malloc(m * sizeof(int));

    for (int i = 0; i < m; i++) {
        char* apples_item_endptr;
        char* apples_item_str = *(apples_temp + i);
        int apples_item = strtol(apples_item_str, &apples_item_endptr, 10);

        if (apples_item_endptr == apples_item_str || *apples_item_endptr != '\0') { exit(EXIT_FAILURE); }

        *(apples + i) = apples_item;
    }

    int apples_count = m;

    char** oranges_temp = split_string(readline());

    int* oranges = malloc(n * sizeof(int));

    for (int i = 0; i < n; i++) {
        char* oranges_item_endptr;
        char* oranges_item_str = *(oranges_temp + i);
        int oranges_item = strtol(oranges_item_str, &oranges_item_endptr, 10);

        if (oranges_item_endptr == oranges_item_str || *oranges_item_endptr != '\0') { exit(EXIT_FAILURE); }

        *(oranges + i) = oranges_item;
    }

    int oranges_count = n;

    countApplesAndOranges(s, t, a, b, apples_count, apples, oranges_count, oranges);

    return 0;
}

char* readline() {
    size_t alloc_length = 1024;
    size_t data_length = 0;
    char* data = malloc(alloc_length);

    while (true) {
        char* cursor = data + data_length;
        char* line = fgets(cursor, alloc_length - data_length, stdin);

        if (!line) { break; }

        data_length += strlen(cursor);

        if (data_length < alloc_length - 1 || data[data_length - 1] == '\n') { break; }

        size_t new_length = alloc_length << 1;
        data = realloc(data, new_length);

        if (!data) { break; }

        alloc_length = new_length;
    }

    if (data[data_length - 1] == '\n') {
        data[data_length - 1] = '\0';
    }

    data = realloc(data, data_length);

    return data;
}

char** split_string(char* str) {
    char** splits = NULL;
    char* token = strtok(str, " ");

    int spaces = 0;

    while (token) {
        splits = realloc(splits, sizeof(char*) * ++spaces);
        if (!splits) {
            return splits;
        }

        splits[spaces - 1] = token;

        token = strtok(NULL, " ");
    }

    return splits;
}

인자들이 무엇을 가리키는지 알면 너무 쉽게풀리는 문제였다.

반복문을 사용해 apple tree와 orange tree를 기준으로 떨어진 사과와 오렌지의 상대적인 거리를 절대적인 거리로 바꾼다.

그리고 조건문을 사용해 집의 영역내에 있는 과일의 수를 세어 출력한다.