代码

// P2: duck.ac 内存路径探针（无 clone）
// 预期：~150-300ms，内存 ~390MB => mmap + 预触 + 顺序读正常
// TLE/RE => mmap 路径有问题；内存 24KB => mmap 失败
#include <cstdint>
#include <sys/mman.h>

void sort(unsigned* a, int n) {
  (void)a;
  (void)n;
  volatile unsigned* v = (volatile unsigned*)mmap(
      nullptr, 400000000UL, PROT_READ | PROT_WRITE,
      MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
  if (v == (volatile unsigned*)-1) return;
  for (size_t i = 0; i < 400000000UL; i += 4096) *(volatile char*)((char*)v + i) = 0;
  unsigned s = 0;
  for (size_t i = 0; i < 100000000UL; i += 16) s += v[i];
  if (s == 0xdeadbeefu) *const_cast<unsigned*>(v) = s;
}

评测结果