50092. Pointer Chasing

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "chasing.h"

static inline int is_ABC(char* s){
    return s[0] == 'A' || s[0] == 'B' || s[0] == 'C';
}

static inline int is_num(char* s){
    int n = strlen(s);
    for(int i = 0; i < n; i++){
        if(!isdigit(s[i])) return 0;
    }
    return 1;
}

static inline int map_char(char* s){
    return s[0] - 'A';
}

void chasing(int **A[], int a, int *B[], int b, int C[], int c){
    memset(A, 0, sizeof(A[0])*a);
    memset(B, 0, sizeof(B[0])*b);
    int arr_sizes[3] = {a, b, c};

    char ipt[64];
    while(fgets(ipt, 64, stdin) != NULL){
        char* s[5];
        s[0] = strtok(ipt, " \n");
        for(int i = 1; i < 5; i++) s[i] = strtok(NULL, " \n");

        if((!s[0]) || (!s[1]) || (!s[2]) || (!s[3]) || (s[4])) {printf("0\n"); continue;}
        if(strlen(s[0]) != 1 || strlen(s[2]) !=  1 || !is_ABC(s[0]) || !is_ABC(s[2])) {printf("0\n"); continue;}
        if(!is_num(s[1]) || !is_num(s[3])) {printf("0\n"); continue;}


        int f_array = map_char(s[0]), t_array = map_char(s[2]);
        if(t_array - f_array != 1) {printf("0\n"); continue;}

        int f_int = atoi(s[1]), t_int = atoi(s[3]);
        if(f_int >= arr_sizes[f_array] || t_int >= arr_sizes[t_array]
        || f_int < 0 || t_int < 0) {printf("0\n"); continue;}

        if(f_array == 0) A[f_int] = &B[t_int];
        else B[f_int] = &C[t_int];
        printf("1\n");
    }
}