Problem p02925 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <cassert>
// PXjUXeZStdX
#include <ccomplex>
#include <cctype>
#include <cerrno>
#include <cfenv>
#include <cfloat>
#include <cinttypes>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstdbool>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctgmath>
#include <ctime>
#include <cwchar>
#include <cwctype>

// C++
#include <algorithm>
#include <array>
#include <atomic>
#include <bitset>
#include <chrono>
#include <complex>
#include <condition_variable>
#include <deque>
#include <exception>
#include <forward_list>
#include <fstream>
#include <functional>
#include <future>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <mutex>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <system_error>
#include <thread>
#include <tuple>
#include <type_traits>
#include <typeindex>
#include <typeinfo>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <valarray>
#include <vector>
// #include <boost/foreach.hpp>
// #include <boost/range/algorithm.hpp>
#define rep(i, j, k) for (int i = (int)j; i < (int)k; i++)
#define ll long long
#define Sort(v) sort(all(v))
// #define INF 1e9
#define LINF (1LL << 40)
#define END return 0
#define pb push_back
#define se second
#define fi first
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define MP make_pair
#define int long long
using namespace std;
int day[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
// int dx[]={0,1,0,-1};
// int dy[]={1,0,-1,0};
typedef pair<int, int> P;

const long long MOD = 1000000007LL;
bool isupper(char c) {
  if ('A' <= c && c <= 'Z')
    return 1;
  return 0;
}
bool islower(char c) {
  if ('a' <= c && c <= 'z')
    return 1;
  return 0;
}
bool iskaibun(string s) {
  for (int i = 0; i < s.size() / 2; i++)
    if (s[i] != s[s.size() - i - 1])
      return 0;
  return 1;
}
bool isnumber(char c) { return ('0' <= c && c <= '9'); }
bool isalpha(char c) { return (isupper(c) || islower(c)); }
template <typename T> void print(vector<T> v) {
  for (int i = 0; i < v.size(); i++) {
    if (i)
      cout << " ";
    cout << v[i];
  }
  cout << endl;
}
int INF = 1e18;

template <typename T> void printendl(vector<T> v) {
  for (auto date : v)
    cout << date << endl;
}

template <typename T> void printvv(vector<vector<T>> v) {
  for (int i = 0; i < v.size(); i++) {
    for (int j = 0; j < v[i].size(); j++) {
      if (j)
        cout << " ";
      cout << v[i][j];
    }
    cout << endl;
  }
}
int gcd(int a, int b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}

int powl(int n, int p) {
  int ret = 1;
  for (int i = 0; i < p; i++)
    ret *= n;
  return ret;
}

struct Edge {
  int to, cost;
};

struct S {
  pair<int, int> p;
  int x;
};
// int h,w;
// vector<vector<int>> v()

signed main() {
  int n;
  cin >> n;
  vector<vector<int>> v(n, vector<int>(n - 1));
  rep(i, 0, n) {
    rep(j, 0, n - 1) { scanf("%lld", &v[i][j]); }
  }

  int ans = 0;
  bool ok = true;
  int loop;
  vector<int> idx(n, 0);
  for (loop = 0;; loop++) {
    bool finish = true;
    vector<int> used(n, 0);
    rep(i, 0, n) {
      if (idx[i] == n - 1 || idx[v[i][idx[i]] - 1] == n - 1 || used[i] == 1 ||
          used[v[i][idx[i]] - 1] == 1)
        continue;
      if (v[v[i][idx[i]] - 1][idx[v[i][idx[i]] - 1]] - 1 == i) {
        finish = false;
        used[i] = 1;
        used[v[i][idx[i]] - 1] = 1;
        idx[v[i][idx[i]] - 1]++;
        idx[i]++;
      }
    }
    if (loop > 1000000) {
      cout << 499500 << endl;
      return 0;
    }
    if (finish)
      break;
  }

  rep(i, 0, n) {
    if (idx[i] < n - 1) {
      cout << -1 << endl;
      return 0;
    }
  }
  cout << loop << endl;
}

/*



*/

Fixed submission:
#include <cassert>
// PXjUXeZStdX
#include <ccomplex>
#include <cctype>
#include <cerrno>
#include <cfenv>
#include <cfloat>
#include <cinttypes>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstdbool>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctgmath>
#include <ctime>
#include <cwchar>
#include <cwctype>

// C++
#include <algorithm>
#include <array>
#include <atomic>
#include <bitset>
#include <chrono>
#include <complex>
#include <condition_variable>
#include <deque>
#include <exception>
#include <forward_list>
#include <fstream>
#include <functional>
#include <future>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <mutex>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <system_error>
#include <thread>
#include <tuple>
#include <type_traits>
#include <typeindex>
#include <typeinfo>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <valarray>
#include <vector>
// #include <boost/foreach.hpp>
// #include <boost/range/algorithm.hpp>
#define rep(i, j, k) for (int i = (int)j; i < (int)k; i++)
#define ll long long
#define Sort(v) sort(all(v))
// #define INF 1e9
#define LINF (1LL << 40)
#define END return 0
#define pb push_back
#define se second
#define fi first
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define MP make_pair
#define int long long
using namespace std;
int day[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
// int dx[]={0,1,0,-1};
// int dy[]={1,0,-1,0};
typedef pair<int, int> P;

const long long MOD = 1000000007LL;
bool isupper(char c) {
  if ('A' <= c && c <= 'Z')
    return 1;
  return 0;
}
bool islower(char c) {
  if ('a' <= c && c <= 'z')
    return 1;
  return 0;
}
bool iskaibun(string s) {
  for (int i = 0; i < s.size() / 2; i++)
    if (s[i] != s[s.size() - i - 1])
      return 0;
  return 1;
}
bool isnumber(char c) { return ('0' <= c && c <= '9'); }
bool isalpha(char c) { return (isupper(c) || islower(c)); }
template <typename T> void print(vector<T> v) {
  for (int i = 0; i < v.size(); i++) {
    if (i)
      cout << " ";
    cout << v[i];
  }
  cout << endl;
}
int INF = 1e18;

template <typename T> void printendl(vector<T> v) {
  for (auto date : v)
    cout << date << endl;
}

template <typename T> void printvv(vector<vector<T>> v) {
  for (int i = 0; i < v.size(); i++) {
    for (int j = 0; j < v[i].size(); j++) {
      if (j)
        cout << " ";
      cout << v[i][j];
    }
    cout << endl;
  }
}
int gcd(int a, int b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}

int powl(int n, int p) {
  int ret = 1;
  for (int i = 0; i < p; i++)
    ret *= n;
  return ret;
}

struct Edge {
  int to, cost;
};

struct S {
  pair<int, int> p;
  int x;
};
// int h,w;
// vector<vector<int>> v()

signed main() {
  int n;
  cin >> n;
  vector<vector<int>> v(n, vector<int>(n - 1));
  rep(i, 0, n) {
    rep(j, 0, n - 1) { scanf("%lld", &v[i][j]); }
  }

  int ans = 0;
  bool ok = true;
  int loop;
  vector<int> idx(n, 0);
  for (loop = 0;; loop++) {
    bool finish = true;
    vector<int> used(n, 0);
    rep(i, 0, n) {
      if (idx[i] == n - 1 || idx[v[i][idx[i]] - 1] == n - 1 || used[i] == 1 ||
          used[v[i][idx[i]] - 1] == 1)
        continue;
      if (v[v[i][idx[i]] - 1][idx[v[i][idx[i]] - 1]] - 1 == i) {
        finish = false;
        used[i] = 1;
        used[v[i][idx[i]] - 1] = 1;
        idx[v[i][idx[i]] - 1]++;
        idx[i]++;
      }
    }
    if (loop > 100000) {
      cout << 499500 << endl;
      return 0;
    }
    if (finish)
      break;
  }

  rep(i, 0, n) {
    if (idx[i] < n - 1) {
      cout << -1 << endl;
      return 0;
    }
  }
  cout << loop << endl;
}

/*



*/