Problem p02574 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
// #pragma GCC optimize(2)
#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <time.h>
#include <vector>

#define X first
#define Y second
#define PB push_back
#define MP make_pair
#define scd(a) scanf("%d", &a)
#define scdd(a, b) scanf("%d%d", &a, &b)
#define scddd(a, b, c) scanf("%d%d%d", &a, &b, &c)
#define ALL(x) x.begin(), x.end()
#define sz(a) ((int)a.size())
#define getmid ((l + r) >> 1)
#define mst(var, val) memset(var, val, sizeof(var))
#define IOS                                                                    \\
  ios::sync_with_stdio(false);                                                 \\
  cin.tie(0)
#define lowbit(x) x & (-x)
#define rep(i, n) for (int i = 0; i < n; ++i)
#define rep1(i, n) for (int i = 1; i <= n; ++i)
#define ls rt << 1
#define rs rt << 1 | 1
using namespace std;
#ifdef local
#define dbg(args...) cout << #args << " -> ", err(args);
void err() { cout << endl; }
template <typename T, typename... Args> void err(T a, Args... args) {
  cout << a << ' ';
  err(args...);
}
#else
#define dbg(args...)
#endif // local

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ll, int> pli;
typedef pair<double, double> pdd;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
const double PI = acos(-1.0);
const long double eps = 1e-8;
const int mod = 1e9 + 7;
const int maxn = 3e5 + 100;
const int N = 1e6 + 1000;
const int M = 500 + 10;
const ll mm = (1LL << 32);

template <class T> inline void read(T &x) {
  x = 0;
  char c = getchar();
  bool f = 0;
  for (; !isdigit(c); c = getchar())
    f ^= c == '-';
  for (; isdigit(c); c = getchar())
    x = x * 10 + (c ^ 48);
  x = f ? -x : x;
}

template <class T> inline void write(T x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  T y = 1;
  int len = 1;
  for (; y <= x / 10; y *= 10)
    ++len;
  for (; len; --len, x %= y, y /= 10)
    putchar(x / y + 48);
}
ll qpow(ll a, ll b, ll mod) {
  ll ans = 1;
  while (b) {
    if (b & 1)
      ans = (ans * a) % mod;
    b >>= 1;
    a = (a * a) % mod;
  }
  return ans;
}

int vis[N], a[N];
int tot, prime[N];
void init() {
  for (int i = 2; i < N; ++i) {
    if (!vis[i])
      prime[tot++] = i;
    for (int j = 0; j < tot; ++j) {
      if (i * prime[j] > N)
        break;
      vis[i * prime[j]] = 1;
    }
  }
}
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int main() {
#ifdef local
  freopen("in.txt", "r", stdin);
#endif // local
  // IOS;cout.tie(0);
  init();
  int n;
  read(n);
  rep1(i, n) read(a[i]);
  int flag = 1, tag = 0;
  for (int i = 1; i <= n; ++i) {
    if (a[i] == 1) {
      tag = 1;
      continue;
    }
    int x = a[i];
    for (int j = 0; j < tot && prime[j] * prime[j] <= x; ++j) {
      if (x % prime[j] == 0) {
        while (x % prime[j] == 0)
          x /= prime[j];
        if (vis[prime[j]] != 0) {
          flag = 0;
          break;
        } else
          vis[prime[j]] = 1;
      }
    }
    if (x != 1) {
      if (vis[x] == 1)
        flag = 0;
      else
        vis[x] = 1;
    }
    if (!flag)
      break;
  }
  if (flag) {
    puts("pairwise coprime");
    return 0;
  }
  int ans = a[1];
  for (int i = 2; i <= n; ++i)
    ans = gcd(ans, a[i]);
  if (ans == 1)
    puts("setwise coprime");
  else
    puts("not coprime");
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
// #pragma GCC optimize(2)
#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <time.h>
#include <vector>

#define X first
#define Y second
#define PB push_back
#define MP make_pair
#define scd(a) scanf("%d", &a)
#define scdd(a, b) scanf("%d%d", &a, &b)
#define scddd(a, b, c) scanf("%d%d%d", &a, &b, &c)
#define ALL(x) x.begin(), x.end()
#define sz(a) ((int)a.size())
#define getmid ((l + r) >> 1)
#define mst(var, val) memset(var, val, sizeof(var))
#define IOS                                                                    \\
  ios::sync_with_stdio(false);                                                 \\
  cin.tie(0)
#define lowbit(x) x & (-x)
#define rep(i, n) for (int i = 0; i < n; ++i)
#define rep1(i, n) for (int i = 1; i <= n; ++i)
#define ls rt << 1
#define rs rt << 1 | 1
using namespace std;
#ifdef local
#define dbg(args...) cout << #args << " -> ", err(args);
void err() { cout << endl; }
template <typename T, typename... Args> void err(T a, Args... args) {
  cout << a << ' ';
  err(args...);
}
#else
#define dbg(args...)
#endif // local

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ll, int> pli;
typedef pair<double, double> pdd;
const int inf = 0x3f3f3f3f;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
const double PI = acos(-1.0);
const long double eps = 1e-8;
const int mod = 1e9 + 7;
const int maxn = 3e5 + 100;
const int N = 1e6 + 1000;
const int M = 500 + 10;
const ll mm = (1LL << 32);

template <class T> inline void read(T &x) {
  x = 0;
  char c = getchar();
  bool f = 0;
  for (; !isdigit(c); c = getchar())
    f ^= c == '-';
  for (; isdigit(c); c = getchar())
    x = x * 10 + (c ^ 48);
  x = f ? -x : x;
}

template <class T> inline void write(T x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  T y = 1;
  int len = 1;
  for (; y <= x / 10; y *= 10)
    ++len;
  for (; len; --len, x %= y, y /= 10)
    putchar(x / y + 48);
}
ll qpow(ll a, ll b, ll mod) {
  ll ans = 1;
  while (b) {
    if (b & 1)
      ans = (ans * a) % mod;
    b >>= 1;
    a = (a * a) % mod;
  }
  return ans;
}

int vis[N], a[N];
int tot, prime[N];
void init() {
  for (int i = 2; i < N; ++i) {
    if (!vis[i])
      prime[tot++] = i;
    for (int j = 0; j < tot; ++j) {
      if (i * prime[j] > N)
        break;
      vis[i * prime[j]] = 1;
    }
  }
}
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int main() {
#ifdef local
  freopen("in.txt", "r", stdin);
#endif // local
  // IOS;cout.tie(0);
  init();
  int n;
  read(n);
  rep1(i, n) read(a[i]);
  int flag = 1, tag = 0;
  for (int i = 1; i <= n; ++i) {
    if (a[i] == 1) {
      tag = 1;
      continue;
    }
    int x = a[i];
    for (int j = 0; j < tot && prime[j] <= x; ++j) {
      if (x % prime[j] == 0) {
        if (vis[prime[j]] == 1) {
          flag = 0;
          break;
        } else
          vis[prime[j]] = 1;
      }
    }
    if (!flag)
      break;
  }
  if (flag) {
    puts("pairwise coprime");
    return 0;
  }
  int ans = a[1];
  for (int i = 2; i <= n; ++i)
    ans = gcd(ans, a[i]);
  if (ans == 1)
    puts("setwise coprime");
  else
    puts("not coprime");
  return 0;
}