代码

#include <iostream>
#include <sys/mman.h>
#include <sys/stat.h>
int main()
{
    constexpr size_t STR_LEN = 2000005;
    int fd = fileno(stdin);
    struct stat sb;
    fstat(fd, &sb);
    char *p = (char *)mmap(NULL, STR_LEN, PROT_READ, MAP_PRIVATE, fd, 0);
    puts(p);
}

评测结果