Problem p02705 (C++) — buggy submission, verdict: Runtime Error

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
ll mod = 1e9 + 7;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep2(i, a, b) for (int i = (a); i < (b); ++i)

template <class T> T maxt(T x, T y) {
  if (x > y)
    return x;
  else
    return y;
}
template <class T> T mint(T x, T y) {
  if (x > y)
    return y;
  else
    return x;
}
// sort(v.begin(), v.end(), [](auto& x, auto& y){return x[1] < y[1];});

// 小数出力
double print_double(double d) { printf("%.6f", d); }

// 約数列挙
vector<ll> divisor(ll n) {
  vector<ll> ret;
  for (ll i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      ret.push_back(i);
      if (i * i != n)
        ret.push_back(n / i);
    }
  }
  sort(begin(ret), end(ret));
  return (ret);
}

// ll combination_mod(int n, int k) {
//   k = mint(k,n-k);
//   ll ans = 1;
//   if (n==0 || k ==0) return ans;
//   rep(i,k) {
//     ans = ans*(n-i)%mod;
//     ans = ans*modinv(i+1)%mod;
//   }
//   return ans;
// }

struct edge {
  int from; // 出発点
  int to;   // 到達点
  ll cost;  // 移動コスト
};

// ベルマンフォード法
vector<ll> bellman_ford(vector<edge> edges, int V, int E, int r,
                        ll INF = 100000000000) {
  vector<ll> cost_to(V, INF);
  cost_to[r] = 0;
  rep(i, V) {
    rep(j, E) {
      edge e = edges[j];
      if (cost_to[e.from] == INF)
        continue;
      if (cost_to[e.to] > cost_to[e.from] + e.cost) {
        cost_to[e.to] = cost_to[e.from] + e.cost;
        if (i == V - 1) {
          printf("NEGATIVE CYCLE\\n");
          return {};
        }
      }
    }
  }
  return cost_to;
}

// combination
const int MAX = 510000;
const int MOD = 1000000007;

long long fac[MAX], finv[MAX], inv[MAX];

void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long COM(int n, int k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

template <class T> inline void chmin(T &a, T b) {
  if (a > b)
    a = b;
}
template <class T> inline void chmax(T &a, T b) {
  if (a < b)
    a = b;
}

// 木上の探索
vector<int> cnt;
void dfs(const vector<vector<int>> &G, int v, int p) {
  for (auto nv : G[v]) {
    if (nv == p)
      continue; // nv が親 p だったらダメ
    dfs(G, nv, v);
  }

  // 帰りがけ時に、部分木サイズを求める
  cnt[v] = 1; // 自分自身
  for (auto c : G[v]) {
    if (c == p)
      continue;
    cnt[v] += cnt[c]; // 子のサイズを加える
  }
}

int main() {
  double r;
  cin >> r;
  double ans = 2 * r * acos(0) * 2;
  cout << ans << endl;
}


Error: -11

Fixed submission:

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
ll mod = 1e9 + 7;
#define rep(i, n) for (int i = 0; i < n; i++)
#define rep2(i, a, b) for (int i = (a); i < (b); ++i)

template <class T> T maxt(T x, T y) {
  if (x > y)
    return x;
  else
    return y;
}
template <class T> T mint(T x, T y) {
  if (x > y)
    return y;
  else
    return x;
}
// sort(v.begin(), v.end(), [](auto& x, auto& y){return x[1] < y[1];});

// 小数出力
double print_double(double d) { printf("%.11f", d); }

// 約数列挙
vector<ll> divisor(ll n) {
  vector<ll> ret;
  for (ll i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      ret.push_back(i);
      if (i * i != n)
        ret.push_back(n / i);
    }
  }
  sort(begin(ret), end(ret));
  return (ret);
}

// ll combination_mod(int n, int k) {
//   k = mint(k,n-k);
//   ll ans = 1;
//   if (n==0 || k ==0) return ans;
//   rep(i,k) {
//     ans = ans*(n-i)%mod;
//     ans = ans*modinv(i+1)%mod;
//   }
//   return ans;
// }

struct edge {
  int from; // 出発点
  int to;   // 到達点
  ll cost;  // 移動コスト
};

// ベルマンフォード法
vector<ll> bellman_ford(vector<edge> edges, int V, int E, int r,
                        ll INF = 100000000000) {
  vector<ll> cost_to(V, INF);
  cost_to[r] = 0;
  rep(i, V) {
    rep(j, E) {
      edge e = edges[j];
      if (cost_to[e.from] == INF)
        continue;
      if (cost_to[e.to] > cost_to[e.from] + e.cost) {
        cost_to[e.to] = cost_to[e.from] + e.cost;
        if (i == V - 1) {
          printf("NEGATIVE CYCLE\\n");
          return {};
        }
      }
    }
  }
  return cost_to;
}

// combination
const int MAX = 510000;
const int MOD = 1000000007;

long long fac[MAX], finv[MAX], inv[MAX];

void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long COM(int n, int k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

template <class T> inline void chmin(T &a, T b) {
  if (a > b)
    a = b;
}
template <class T> inline void chmax(T &a, T b) {
  if (a < b)
    a = b;
}

// 木上の探索
vector<int> cnt;
void dfs(const vector<vector<int>> &G, int v, int p) {
  for (auto nv : G[v]) {
    if (nv == p)
      continue; // nv が親 p だったらダメ
    dfs(G, nv, v);
  }

  // 帰りがけ時に、部分木サイズを求める
  cnt[v] = 1; // 自分自身
  for (auto c : G[v]) {
    if (c == p)
      continue;
    cnt[v] += cnt[c]; // 子のサイズを加える
  }
}

int main() {
  int r;
  cin >> r;
  print_double(2 * r * acos(0) * 2);
}