代码

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>

using u32 = unsigned int;
using u64 = unsigned long long;

constexpr size_t MAXN = 266670;
static u32 f_val[MAXN], *f = f_val + (MAXN >> 1), *p0, *p1, *p2, *p3, *lim;
#define upv(p) (*p = *(p - 1) + *(p + 1), p += 8)
u32 solve(int n, char * s) {
  if (n & 1)
    return 0;
  *f = 1;
  for (int i = 0; i < n; f[-1] = 0, i++) {
    if (s[i] == '(')
      f--;
    else if (s[i] == ')')
      f++;
    else {
      lim = f + std::min(i + 1, n - i - 1);
      p0 = f + ((i & 1) ^ 1), p1 = p0 + 2, p2 = p1 + 2, p3 = p2 + 2;
#pragma GCC ivdep
      while (p3 <= lim) {
        upv(p0), upv(p1), upv(p2), upv(p3);
      }
#pragma GCC ivdep
      while (p0 <= lim) {
        *p0 = *(p0 - 1) + *(p0 + 1);
        p0 += 2;
      }
    }
  }
  return *f;
}

评测结果