善用 namespace

使用 namespace 能使程序可读性更好，便于调试。

// NOI 2018 屠龙勇士 40分部分分代码
#include <algorithm>
#include <cmath>
#include <cstring>
#include <iostream>
using namespace std;
long long n, m, a[100005], p[100005], aw[100005], atk[100005];
 
namespace one_game {
// 其实namespace里也可以声明变量
void solve() {
  for (int y = 0;; y++)
    if ((a[1] + p[1] * y) % atk[1] == 0) {
      cout << (a[1] + p[1] * y) / atk[1] << endl;
      return;
    }
}
}  // namespace one_game
 
namespace p_1 {
void solve() {
  if (atk[1] == 1) {  // solve 1-2
    sort(a + 1, a + n + 1);
    cout << a[n] << endl;
    return;
  } else if (m == 1) {  // solve 3-4
    long long k = atk[1], kt = ceil(a[1] * 1.0 / k);
    for (int i = 2; i <= n; i++)
      k = aw[i - 1], kt = max(kt, (long long)ceil(a[i] * 1.0 / k));
    cout << k << endl;
  }
}
}  // namespace p_1
 
int main() {
  int T;
  cin >> T;
  while (T--) {
    memset(a, 0, sizeof(a));
    memset(p, 0, sizeof(p));
    memset(aw, 0, sizeof(aw));
    memset(atk, 0, sizeof(atk));
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) cin >> p[i];
    for (int i = 1; i <= n; i++) cin >> aw[i];
    for (int i = 1; i <= m; i++) cin >> atk[i];
    if (n == 1 && m == 1)
      one_game::solve();  // solve 8-13
    else if (p[1] == 1)
      p_1::solve();  // solve 1-4 or 14-15
    else
      cout << -1 << endl;
  }
  return 0;
}