Problem p00904 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common
typedef long long ll;

#define BR "\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #undef NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \
  if (exp != act) {                                                            \
    DUMPLN(exp);                                                               \
    DEBUGLN(act);                                                              \
  }
#define STOP(e)                                                                \
  CHECK(e, true);                                                              \
  if (!(e))                                                                    \
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

// ind -> V から V->ind (注:単射)
template <typename T> map<T, int> rev(const vector<T> &xs) {
  map<T, int> rev;
  REP(i, (int)xs.size()) rev.insert(make_pair(xs[i], i));
  return rev;
}

template <typename T, typename V> inline T mod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
int INF = 1 << 28;

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

struct Edge {
  int from, to, d, c;
  Edge(int u, int v, int d, int c) : from(u), to(v), d(d), c(c){};
};
struct Task {
  int prev, pos, d;
  Task(int prev, int pos, int d) : prev(prev), pos(pos), d(d){};
  bool operator>(const Task &r) const { return d > r.d; }
};
typedef vector<vector<Edge>> Graph;

vector<int> dijkstra(const Graph &g, const int s, vector<int> &prev) {
  const int V = g.size();
  vector<int> d(V, INF);
  d[s] = 0;
  fill(ALL(prev), -2);
  priority_queue<Task, vector<Task>, greater<Task>> que;
  que.push(Task(-1, s, 0));
  while (!que.empty()) {
    Task task = que.top();
    que.pop();
    // if(prev[task.pos]!=-2)continue;
    if (d[task.pos] < task.d)
      continue;
    prev[task.pos] = task.prev;
    EACH(e, g[task.pos]) {
      if (d[e->to] > d[e->from] + e->d) {
        d[e->to] = d[e->from] + e->d;
        que.push(Task(e->from, e->to, d[e->to]));
      }
    }
  }
  return d;
}
vector<int> dijkstra(const Graph &g, const int s) {
  vector<int> prev(g.size());
  return dijkstra(g, s, prev);
}

typedef int T;
T gcd(T a, T b) { return b == 0 ? a : gcd(b, a % b); }

class Main {
public:
  int N, M;
  vector<vector<Edge>> es;
  void run() {
    int N;
    cin >> N;
    REP(i, N) {
      int p, q;
      cin >> p >> q;
      int pq = p * p + q * q;

      bool prime = true;

      REP(m, pq + 1) REP(n, pq + 1) {
        int mn = m * m + n * n;
        if (mn > pq)
          continue;
        if (mn <= 1 || mn == pq)
          continue;
        if (pq % mn == 0) {
          prime = false;
        }
      }
      cout << (prime ? "P" : "C") << endl;
    }
  }
};

int main() {
  Main().run();
  return 0;
}

Fixed submission:
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common
typedef long long ll;

#define BR "\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #undef NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \
  if (exp != act) {                                                            \
    DUMPLN(exp);                                                               \
    DEBUGLN(act);                                                              \
  }
#define STOP(e)                                                                \
  CHECK(e, true);                                                              \
  if (!(e))                                                                    \
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

// ind -> V から V->ind (注:単射)
template <typename T> map<T, int> rev(const vector<T> &xs) {
  map<T, int> rev;
  REP(i, (int)xs.size()) rev.insert(make_pair(xs[i], i));
  return rev;
}

template <typename T, typename V> inline T mod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
int INF = 1 << 28;

int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

struct Edge {
  int from, to, d, c;
  Edge(int u, int v, int d, int c) : from(u), to(v), d(d), c(c){};
};
struct Task {
  int prev, pos, d;
  Task(int prev, int pos, int d) : prev(prev), pos(pos), d(d){};
  bool operator>(const Task &r) const { return d > r.d; }
};
typedef vector<vector<Edge>> Graph;

vector<int> dijkstra(const Graph &g, const int s, vector<int> &prev) {
  const int V = g.size();
  vector<int> d(V, INF);
  d[s] = 0;
  fill(ALL(prev), -2);
  priority_queue<Task, vector<Task>, greater<Task>> que;
  que.push(Task(-1, s, 0));
  while (!que.empty()) {
    Task task = que.top();
    que.pop();
    // if(prev[task.pos]!=-2)continue;
    if (d[task.pos] < task.d)
      continue;
    prev[task.pos] = task.prev;
    EACH(e, g[task.pos]) {
      if (d[e->to] > d[e->from] + e->d) {
        d[e->to] = d[e->from] + e->d;
        que.push(Task(e->from, e->to, d[e->to]));
      }
    }
  }
  return d;
}
vector<int> dijkstra(const Graph &g, const int s) {
  vector<int> prev(g.size());
  return dijkstra(g, s, prev);
}

typedef int T;
T gcd(T a, T b) { return b == 0 ? a : gcd(b, a % b); }

class Main {
public:
  int N, M;
  vector<vector<Edge>> es;
  void run() {
    int N;
    cin >> N;
    REP(i, N) {
      int p, q;
      cin >> p >> q;
      int pq = p * p + q * q;

      bool prime = true;

      REP(m, pq + 1) REP(n, pq + 1) {
        int mn = m * m + n * n;
        if (mn > pq)
          break;
        if (mn <= 1 || mn == pq)
          continue;
        if (pq % mn == 0) {
          prime = false;
        }
      }
      cout << (prime ? "P" : "C") << endl;
    }
  }
};

int main() {
  Main().run();
  return 0;
}