Problem p02574 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>

#define A_MAX 1000000
#define A_MAX_HALF 500000

using namespace std;

int min_factor[A_MAX + 1];
int q[A_MAX + 1];
int a[A_MAX + 1];
vector<int> primes{
    2,   3,   5,   7,   11,  13,  17,  19,  23,  29,  31,  37,  41,  43,
    47,  53,  59,  61,  67,  71,  73,  79,  83,  89,  97,  101, 103, 107,
    109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181,
    191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263,
    269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349,
    353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433,
    439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521,
    523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613,
    617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701,
    709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809,
    811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887,
    907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997};
int N;

// 入力読み込みは uzzy 氏のコードを真似した
const int cm = 1 << 26;
char cn[cm], *ci = cn, ct;
inline int getint() {
  int A = 0;
  while ((ct = *ci++) >= '0')
    A = A * 10 + ct - '0';
  return A;
}

int main() {
  fread(cn, 1, cm, stdin);

  for (int i = 2; i <= A_MAX_HALF; ++i) {
    if (!min_factor[i]) {
      min_factor[i] = i;
    }
    int min_factor_i = min_factor[i];
    for (int p : primes) {
      int n = i * p;
      if (n > A_MAX) {
        break;
      }
      min_factor[n] = p;
      if (p == min_factor_i) {
        q[n] = q[i];
        break;
      } else {
        q[n] = i;
      }
    }
  }

  N = getint();
  for (int i = 0; i < N; ++i) {
    ++a[getint()];
  }

  int is_pairwise_coprime = 1;
  for (int n = A_MAX; n > 1; --n) {
    int an = a[n];
    if (an) {
      if (an > 1) {
        if (an == N) {
          printf("not coprime\\n");
          return 0;
        }
        is_pairwise_coprime = 0;
      }
      a[min_factor[n]] += an;
      a[q[n]] += an;
    }
  }
  if (is_pairwise_coprime) {
    printf("pairwise coprime\\n");
  } else {
    printf("setwise coprime\\n");
  }

  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>

#define A_MAX 1000000
#define A_MAX_HALF 500000

using namespace std;

int min_factor[A_MAX + 1];
int q[A_MAX + 1];
int a[A_MAX + 1];
vector<int> primes{
    2,   3,   5,   7,   11,  13,  17,  19,  23,  29,  31,  37,  41,  43,
    47,  53,  59,  61,  67,  71,  73,  79,  83,  89,  97,  101, 103, 107,
    109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181,
    191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263,
    269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349,
    353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433,
    439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521,
    523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613,
    617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701,
    709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809,
    811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887,
    907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997};
int N;

// 入力読み込みは uzzy 氏のコードを真似した
const int cm = 1 << 22;
char cn[cm], *ci = cn, ct;
inline int getint() {
  int A = 0;
  while ((ct = *ci++) >= '0')
    A = A * 10 + ct - '0';
  return A;
}

int main() {
  fread(cn, 1, cm, stdin);

  for (int i = 2; i <= A_MAX_HALF; ++i) {
    if (!min_factor[i]) {
      min_factor[i] = i;
    }
    int min_factor_i = min_factor[i];
    for (int p : primes) {
      int n = i * p;
      if (n > A_MAX) {
        break;
      }
      min_factor[n] = p;
      if (p == min_factor_i) {
        q[n] = q[i];
        break;
      } else {
        q[n] = i;
      }
    }
  }

  N = getint();
  for (int i = 0; i < N; ++i) {
    ++a[getint()];
  }

  int is_pairwise_coprime = 1;
  for (int n = A_MAX; n > 1; --n) {
    int an = a[n];
    if (an) {
      if (an > 1) {
        if (an == N) {
          printf("not coprime\\n");
          return 0;
        }
        is_pairwise_coprime = 0;
      }
      a[min_factor[n]] += an;
      a[q[n]] += an;
    }
  }
  if (is_pairwise_coprime) {
    printf("pairwise coprime\\n");
  } else {
    printf("setwise coprime\\n");
  }

  return 0;
}