is_steal.c

/* gcc -Wall -Wno-char-subscripts -o is_steal is_steal.c */

#include <stdio.h>

int is_steal(const char *base, const char *steal) {
    char count[26] = {0};
    int bl, sl;

    for(bl = sl = 0; base[bl]; bl++) {
        if(count[base[bl]] > 0) {
            count[base[bl]]--;
        } else {
            for(; steal[sl] && steal[sl] != base[bl]; sl++, count[steal[sl]]++);
            if(!steal[sl]) return 0;
        }
    }
    for(; sl <= bl && steal[sl]; sl++);

    return sl > bl;
}

int main(int argc, const char **argv) {
    if(is_steal(argv[1], argv[2])) {
        puts("true");
        return 0;
    } else {
        puts("false");
        return 1;
    }
}