Problem p03634 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <list>
#include <math.h>
#include <numeric>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<ULL> VULL;
typedef vector<VLL> VVLL;

class MYCP {
public:
  static const LL MOD_CONST_ATCODER = (LL)1000 * 1000 * 1000 + 7;

  static LL DebugFlag;

  // 数値を区切って文字列にする
  static string MakeString_LongLong(vector<long long> const &numbers,
                                    string const &str) {
    if (numbers.size() == 0)
      return "";
    string result = "" + to_string(numbers[0]);
    for (long long i = 1; i < numbers.size(); i++) {
      result += str;
      result += to_string(numbers[i]);
    }

    return result;
  }

  // 空白で区切る為のオーバーロード
  static string MakeString_LongLong(vector<long long> const &numbers) {
    if (numbers.size() == 0)
      return "";
    string result = "" + to_string(numbers[0]);
    for (long long i = 1; i < numbers.size(); i++) {
      result += " ";
      result += to_string(numbers[i]);
    }

    return result;
  }

  // 文字列の配列を改行を挟んでまとめる
  static string MakeString_VectorString(vector<string> const &str) {
    string result = "";
    for (long long i = 0; i < str.size(); i++) {
      result += str[i] + "\n";
    }

    return result;
  }

  // 文字列を必要な個数だけ読み取る
  static vector<string> MyReadLineSplit(LL n) {
    vector<string> str(n);
    for (long long i = 0; i < n; i++) {
      std::cin >> str[i];
    }

    return str;
  }

  // 数値を必要な個数だけ読み取る
  static vector<long long> ReadInts(long long number) {
    vector<long long> a(number);
    for (int i = 0; i < number; i++) {
      std::cin >> a[i];
    }

    return a;
  }

  // 渡された自然数が素数ならtureを返す
  static bool PrimeCheck_Int(long long number) {
    if (number < 2)
      return false;

    for (ULL i = 2; i * i <= number; i++) {
      if (number % i == 0)
        return false;
    }

    return true;
  }

  // 渡された数値以下の素数表を作る
  static vector<long long> MakePrimeList(long long n) {
    vector<long long> list;
    LL i, j, p;
    bool flag;
    for (i = 2; i <= n; i++) {
      flag = true;
      for (j = 0; j < list.size(); j++) {

        if (!(list[j] * list[j] <= i))
          break;

        if (i % list[j] == 0) {
          flag = false;
          break;
        }
      }
      if (flag)
        list.push_back(i);
    }

    return list;
  }

  // 文字列の分割
  static vector<string> split(string const &str, char sep) {
    vector<std::string> v;    // 分割結果を格納するベクター
    auto first = str.begin(); // テキストの最初を指すイテレータ
    while (first != str.end()) { // テキストが残っている間ループ
      auto last = first;         // 分割文字列末尾へのイテレータ
      while (last != str.end() &&
             *last != sep) // 末尾 or セパレータ文字まで進める
        last++;
      v.push_back(string(first, last)); // 分割文字を出力
      if (last != str.end())
        last++;
      first = last; // 次の処理のためにイテレータを設定
    }
    return v;
  }

  // 合計を求める
  static LL Sum(vector<LL> a) {
    LL i, sum = 0;

    for (i = 0; i < a.size(); i++) {
      sum += a[i];
    }

    return sum;
  }

  // 小文字ならtrueを返す
  static bool Komoji(char a) {
    if (a >= 'a' && a <= 'z')
      return true;

    return false;
  }

  // 大文字ならtrueを返す
  static bool Oomoji(char a) {
    if (a >= 'A' && a <= 'Z')
      return true;

    return false;
  }

  // 切り上げの整数値割り算
  static LL KiriageWarizan(LL a, LL b) {
    LL result = a / b;

    if (a % b > 0)
      result++;

    return result;
  }

  // 最大公約数
  static LL GreatestCommonFactor(LL a, LL b) {
    LL temp;
    if (a < b) {
      temp = b;
      b = a;
      a = temp;
    }

    while (true) {
      temp = a % b;
      a = b;
      b = temp;
      if (b == 0)
        break;
    }

    return a;
  }

  // 最小公倍数
  static LL LeastCommonMultiple(LL a, LL b) {
    return (a / GreatestCommonFactor(a, b)) * b;
  }

  // 素因数分解
  static vector<VLL> PrimeFactorization(LL n) {
    VLL p_list, s_list;

    LL i, j, k, count;

    for (i = 2; n > 1; i++) {
      if (i * i > n) {
        p_list.push_back(n);
        s_list.push_back(1);
        break;
      }

      if (n % i == 0) {
        count = 0;
        while (n % i == 0) {
          n /= i;
          count++;
        }

        p_list.push_back(i);
        s_list.push_back(count);
      }
    }

    vector<VLL> result;
    result.push_back(p_list);
    result.push_back(s_list);

    return result;
  }

  // 組み合わせ nCr
  static LL Combination(LL n, LL r) {
    r = min(r, n - r);

    VLL p(n + 1, 0);

    LL i, j, k, a, b, c;

    for (i = 1; i <= r; i++) {
      auto temp = MYCP::PrimeFactorization(i);

      for (j = 0; j < temp[0].size(); j++) {
        p[temp[0][j]] -= temp[1][j];
      }

      a = i + n - r;
      temp = MYCP::PrimeFactorization(a);

      for (j = 0; j < temp[0].size(); j++) {
        p[temp[0][j]] += temp[1][j];
      }
    }

    LL result = 1;

    for (i = 0; i < p.size(); i++) {
      if (p[i] > 0) {

        for (j = 0; j < p[i]; j++) {
          result *= i;
          result %= MYCP::MOD_CONST_ATCODER;
        }
      }
    }

    return result;
  }

  // 符号
  static LL sign(LL const x) {
    if (x > 0)
      return 1;
    if (x < 0)
      return -1;
    return 0;
  }

  // 円周率
  static double PI() { return (double)3.1415926535898; }

  // 指定した桁でdoubleを出す
  static void CoutDoubleKeta(double a, LL keta) {
    cout << setprecision(keta) << a << flush;
  }

  // 数値の出力
  static void CoutVectorLL(VLL list) {
    LL i, j, k, n;
    n = list.size();

    for (i = 0; i < n - 1; i++) {
      cout << list[i] << " ";
    }

    cout << list[n - 1] << flush;
  }

  // VLLの配列をソートする
  static void Sort_VLL(VVLL &x, LL n) {
    auto function = [&](VLL a, VLL b) { return a[n] < b[n]; };

    sort(x.begin(), x.end(), function);
  }

  // デバッグ用出力
  static LL DebugPrintf(string output) {

    if (MYCP::DebugFlag) {
      std::cout << output << endl;
    }

    return MYCP::DebugFlag;
  }

  // デバッグ用入力
  static LL DebugCin() {
    LL a;

    if (MYCP::DebugFlag) {
      cin >> a;
    }

    return a;
  }
};
LL MYCP::DebugFlag = 0;

// 累積和を求めるクラス
class Ruisekiwa {
private:
  vector<LL> list;

public:
  void MakeArray(vector<LL> data) {
    LL i;
    list = data;
    list.push_back(0);
    list[0] = 0;
    for (i = 1; i < list.size(); i++) {
      list[i] = list[i - 1] + data[i - 1];
    }
  }

  LL Sum(LL start, LL end) {
    if (end < start) {
      std::cout << "startがendより大きいです";
      return 0;
    }
    if (start < 0 || end >= list.size()) {
      std::cout << "範囲が異常";
      return 0;
    }

    return list[end] - list[start];
  }
};

// n進数を管理するクラス
class N_Number {
public:
  N_Number(LL n, LL keta) {
    this->N_Shinsuu = n;

    VLL temp(keta, 0);
    this->numbers = temp;
  }

  // 数を足す
  void plus(LL a) {
    if (a < 0) {
      a *= (-1);
      this->minus(a);
      return;
    }

    this->numbers[0] += a;
    LL size = this->numbers.size();
    for (LL i = 0; i < size; i++) {
      if (i + 1 < size) {
        this->numbers[i + 1] += this->numbers[i] / this->N_Shinsuu;
      }
      this->numbers[i] %= this->N_Shinsuu;
    }
  }

  // 全ての桁が同じ数字になっていればその数字を返す。それ以外の場合は -1 を返す
  LL check() {
    LL a = this->numbers[0];

    for (LL i = 0; i < this->numbers.size(); i++) {
      if (this->numbers[i] != a)
        return -1;
    }

    return a;
  }

  LL getNumber(LL keta) { return this->numbers[keta]; }

  LL getKeta() { return this->numbers.size(); }

  LL getShinsuu() { return this->N_Shinsuu; }

  void setNumber(LL keta, LL number) {
    if (0 <= number && number < this->getShinsuu()) {
      if (0 <= keta && keta < this->getKeta()) {
        this->numbers[keta] = number;
        return;
      }
    }

    cout << "er" << endl;
  }

  void setAllNumbers(LL number) {
    LL size = this->getKeta(), i;
    for (i = 0; i < size; i++) {
      this->setNumber(i, number);
    }
  }

  string to_string_KetaSoroe() {
    string s = "";
    for (LL i = this->getKeta() - 1; i >= 0; i--) {
      s += to_string(this->getNumber(i));
    }

    return s;
  }

private:
  void minus(LL a) {
    LL i, j, k, zettaiti = abs(a);

    k = MYCP::KiriageWarizan(zettaiti, this->N_Shinsuu);
    j = k * (this->N_Shinsuu - 1);

    for (i = 0; i < this->getKeta(); i++) {
      this->numbers[i] += j;
    }

    this->numbers[0] += k - a;
    this->plus(0);
  }

  VLL numbers;
  LL N_Shinsuu;
};

// UnionFind
class Union_Find {
private:
  VLL tree;
  VLL count;

  LL root(LL a) {
    if (this->tree[a] == a)
      return a;
    return this->tree[a] = this->root(this->tree[a]);
  }

public:
  Union_Find(LL n) {
    VLL set(n);
    this->tree = set;
    this->count = set;

    for (LL i = 0; i < n; i++) {
      this->tree[i] = i;
      this->count[i] = 1;
    }
  }

  void unite(LL a, LL b) {
    LL x, y;

    if (!this->Check(a, b)) {
      x = this->getCount(a) + getCount(b);

      y = this->root(a);
      this->count[y] = x;

      y = this->root(b);
      this->count[y] = x;
    }

    x = this->root(a);
    y = this->root(b);

    this->tree[x] = y;
  }

  bool Check(LL a, LL b) { return this->root(a) == this->root(b); }

  LL getCount(LL index) {
    LL temp = this->root(index);
    return this->count[temp];
  }
};

// プラスマイナス無限に対応したlong long型
class INF_LONG_LONG {
private:
  LL inf, n;

public:
  // コンストラクタ
  INF_LONG_LONG(LL a) {
    this->n = a;
    this->inf = 0;

    this->Syusei();
  }

  INF_LONG_LONG() { *this = INF_LONG_LONG(0); }

  INF_LONG_LONG(INF_LONG_LONG const &a) {
    this->n = a.n;
    this->inf = a.inf;

    this->Syusei();
  }

  // ゲッター
  LL getN() const { return this->n; }

  LL getInf() const { return this->inf; }

  // 正の無限大生成
  static INF_LONG_LONG plus_inf() {
    INF_LONG_LONG a;
    a.n = 0;
    a.inf = 1;

    a.Syusei();

    return a;
  }

  // 負の無限大生成
  static INF_LONG_LONG minus_inf() {
    INF_LONG_LONG a;
    a.n = 0;
    a.inf = -1;

    a.Syusei();

    return a;
  }

  // 符号を取得
  LL sign() const {
    if (this->inf != 0) {
      return this->inf;
    }

    return MYCP::sign(this->n);
  }

  // 代入演算子
  INF_LONG_LONG operator=(INF_LONG_LONG const &b) {
    this->n = b.n;
    this->inf = b.inf;

    this->Syusei();

    return *this;
  }

  INF_LONG_LONG operator=(LL const &b) {
    *this = INF_LONG_LONG(b);

    this->Syusei();

    return *this;
  }

  // 比較演算子
  bool operator==(INF_LONG_LONG const &b) const {
    if (this->n == b.n && this->inf == b.inf)
      return true;

    return false;
  }

  bool operator!=(INF_LONG_LONG const &b) const { return !(*this == b); }

  bool operator<(INF_LONG_LONG const &b) const {
    if (this->inf < b.inf)
      return true;

    if (this->inf > b.inf)
      return false;

    return this->n < b.n;
  }

  bool operator>(INF_LONG_LONG const &b) const { return b < *this; }

  bool operator<=(INF_LONG_LONG const &b) const { return !(*this > b); }

  bool operator>=(INF_LONG_LONG const &b) const { return !(*this < b); }

  // 算術演算子
  INF_LONG_LONG operator+(INF_LONG_LONG const &b) const {
    if (max(this->inf, b.inf) > 0)
      return INF_LONG_LONG::plus_inf();
    if (min(this->inf, b.inf) < 0)
      return INF_LONG_LONG::minus_inf();

    auto ans = *this;
    ans.n += b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator*(INF_LONG_LONG const &b) const {

    if (*this == INF_LONG_LONG(0) || b == INF_LONG_LONG(0)) {
      return INF_LONG_LONG(0);
    }

    if (this->inf != 0 || b.inf != 0) {
      LL s = this->sign() * b.sign();

      INF_LONG_LONG ans(0);
      ans.n = 0;
      ans.inf = s;

      ans.Syusei();

      return ans;
    }

    INF_LONG_LONG ans(0);

    ans.n = this->n * b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator-(INF_LONG_LONG const &b) const {
    auto ans = (*this + (INF_LONG_LONG(-1) * b));
    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator/(INF_LONG_LONG const &b) const {
    if (b == INF_LONG_LONG(0)) {
      LL a = this->n / b.n;

      return INF_LONG_LONG(a);
    }

    if (b.inf != 0) {
      return INF_LONG_LONG(0);
    }

    if (*this == INF_LONG_LONG(0)) {
      return INF_LONG_LONG(0);
    }

    if (this->inf != 0) {
      LL s = this->sign() * b.sign();

      return INF_LONG_LONG::plus_inf() * INF_LONG_LONG(s);
    }

    INF_LONG_LONG ans;

    ans.n = this->n / b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator%(INF_LONG_LONG const &b) const {
    if (this->inf == 0 && b.inf == 0) {
      INF_LONG_LONG ans;

      ans.n = this->n % b.n;

      ans.Syusei();

      return ans;
    }

    auto x = *this / b;
    x.Syusei();
    auto ans = *this - b * x;
    ans.Syusei();

    return ans;
  }

  // 複合代入演算子
  INF_LONG_LONG operator+=(INF_LONG_LONG const &b) {
    auto ans = *this + b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator-=(INF_LONG_LONG const &b) {
    auto ans = *this - b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator*=(INF_LONG_LONG const &b) {
    auto ans = *this * b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator/=(INF_LONG_LONG const &b) {
    auto ans = *this / b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator%=(INF_LONG_LONG const &b) {
    auto ans = *this % b;
    *this = ans;

    return *this;
  }

  // 符号演算子
  INF_LONG_LONG operator+() const { return *this; }

  INF_LONG_LONG operator-() const { return *this * INF_LONG_LONG(-1); }

  // 前置きインクリメント・デクリメント
  INF_LONG_LONG operator++() {
    this->n++;
    this->Syusei();

    return *this;
  }

  INF_LONG_LONG operator--() {
    this->n--;
    this->Syusei();

    return *this;
  }

  // 後置きインクリメント・デクリメント
  INF_LONG_LONG operator++(int) {
    auto copy = *this;
    ++(*this);
    return copy;
  }

  INF_LONG_LONG operator--(int) {
    auto copy = *this;
    --(*this);
    return copy;
  }

  // 文字列への変換
  string ToString() const {
    if (this->inf == 1) {
      return "+INF";
    }

    if (this->inf == -1) {
      return "-INF";
    }

    return to_string(this->n);
  }

private:
  void Syusei() {
    if (this->inf != 0) {
      this->n = 0;
    }
  }
};
typedef INF_LONG_LONG ILL_TYPE;
typedef vector<ILL_TYPE> VILL_TYPE;
typedef vector<VILL_TYPE> VVILL_TYPE;

// ワーシャルフロイド
class WarshallFloyd {
public:
  // 最短距離を記録
  VVILL_TYPE d;

  // 頂点数
  LL v;

  // vは頂点数、edge_cost_listは辺の情報{始点、終点、コスト}の配列。無向グラフの場合、逆矢印の辺に注意。
  WarshallFloyd(LL v, VVLL edge_cost_list) {
    this->v = v;

    this->d = VVILL_TYPE(v, VILL_TYPE(v, ILL_TYPE::plus_inf()));

    LL i, j, k, a, b, c;

    for (i = 0; i < edge_cost_list.size(); i++) {
      a = edge_cost_list[i][0];
      b = edge_cost_list[i][1];
      c = edge_cost_list[i][2];

      this->d[a][b] = ILL_TYPE(c);
    }

    for (i = 0; i < v; i++) {
      this->d[i][i] = ILL_TYPE(0);
    }

    // ここから計算
    for (k = 0; k < v; k++) {
      for (i = 0; i < v; i++) {
        for (j = 0; j < v; j++) {
          d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
        }
      }
    }
  }
};

// ベルマンフォード
class BellmanFord {
public:
  // 辺のリスト
  VVILL_TYPE edge;

  // 頂点数、辺数
  LL v, e;

  // 始点
  LL s;

  // 最短距離
  VILL_TYPE d;

  // vは頂点数、startは始点、edge_cost_listは辺の情報{始点、終点、コスト}の配列。
  BellmanFord(LL v, LL start, VVLL edge_cost_list) {
    this->v = v;
    this->s = start;
    this->e = edge_cost_list.size();
    this->d = VILL_TYPE(v, ILL_TYPE::plus_inf());
    this->d[start] = 0;

    LL i, j, k;
    for (i = 0; i < this->e; i++) {
      VILL_TYPE temp;
      LL a, b, c;
      a = edge_cost_list[i][0];
      b = edge_cost_list[i][1];
      c = edge_cost_list[i][2];

      temp.push_back(ILL_TYPE(a));
      temp.push_back(ILL_TYPE(b));
      temp.push_back(ILL_TYPE(c));

      this->edge.push_back(temp);
    }

    for (i = 0; i < v; i++) {
      bool update = true;

      for (j = 0; j < this->e; j++) {
        ILL_TYPE c;
        LL a, b;
        a = this->edge[j][0].getN();
        b = this->edge[j][1].getN();
        c = this->edge[j][2];

        if (this->d[a] < ILL_TYPE::plus_inf()) {
          if (this->d[a] + c < this->d[b]) {
            update = false;

            this->d[b] = this->d[a] + c;
          }
        }
      }

      if (update)
        break;
    }
  }
};

// ここからメイン
int main(void) {
  MYCP::DebugFlag = 0;

  LL i, j, k, n, m;
  cin >> n;

  vector<VVILL_TYPE> edge(n);

  for (i = 0; i < n - 1; i++) {
    auto temp = MYCP::ReadInts(3);
    temp[0]--;
    temp[1]--;

    VILL_TYPE a;
    a.push_back(ILL_TYPE(temp[1]));
    a.push_back(ILL_TYPE(temp[2]));

    edge[temp[0]].push_back(a);

    swap(temp[0], temp[1]);
    VILL_TYPE reset;
    a = reset;
    a.push_back(ILL_TYPE(temp[1]));
    a.push_back(ILL_TYPE(temp[2]));

    edge[temp[0]].push_back(a);
  }

  LL q;
  cin >> q >> k;
  k--;

  VLL x, y(q);
  x = y;
  for (i = 0; i < q; i++) {
    cin >> x[i] >> y[i];
    x[i]--;
    y[i]--;
  }

  VILL_TYPE d(n, ILL_TYPE::plus_inf());
  d[k] = 0;

  list<LL> ls;
  ls.push_back(k);

  LL count = 0;

  while (ls.size()) {
    count++;

    auto itr = ls.begin();

    for (i = 0; i < edge[*itr].size(); i++) {
      auto a = edge[*itr][i][0].getN();
      auto b = edge[*itr][i][1];

      if (d[*itr] + b < d[a]) {
        d[a] = d[*itr] + b;

        ls.push_back(a);
      }
    }

    ls.pop_front();
  }

  MYCP::DebugPrintf(to_string(count));

  for (i = 0; i < n; i++) {
    string temp = to_string(i) + ":" + to_string(d[i].getN());

    if (d[i].getInf())
      MYCP::DebugPrintf("無限");
    else
      MYCP::DebugPrintf(temp);
  }

  MYCP::DebugPrintf("ここまで");

  for (i = 0; i < q; i++) {
    cout << (d[x[i]] + d[y[i]]).getN() << endl;
  }

  return 0;
}


Fixed submission:
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <list>
#include <math.h>
#include <numeric>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<ULL> VULL;
typedef vector<VLL> VVLL;

class MYCP {
public:
  static const LL MOD_CONST_ATCODER = (LL)1000 * 1000 * 1000 + 7;

  static LL DebugFlag;

  // 数値を区切って文字列にする
  static string MakeString_LongLong(vector<long long> const &numbers,
                                    string const &str) {
    if (numbers.size() == 0)
      return "";
    string result = "" + to_string(numbers[0]);
    for (long long i = 1; i < numbers.size(); i++) {
      result += str;
      result += to_string(numbers[i]);
    }

    return result;
  }

  // 空白で区切る為のオーバーロード
  static string MakeString_LongLong(vector<long long> const &numbers) {
    if (numbers.size() == 0)
      return "";
    string result = "" + to_string(numbers[0]);
    for (long long i = 1; i < numbers.size(); i++) {
      result += " ";
      result += to_string(numbers[i]);
    }

    return result;
  }

  // 文字列の配列を改行を挟んでまとめる
  static string MakeString_VectorString(vector<string> const &str) {
    string result = "";
    for (long long i = 0; i < str.size(); i++) {
      result += str[i] + "\n";
    }

    return result;
  }

  // 文字列を必要な個数だけ読み取る
  static vector<string> MyReadLineSplit(LL n) {
    vector<string> str(n);
    for (long long i = 0; i < n; i++) {
      std::cin >> str[i];
    }

    return str;
  }

  // 数値を必要な個数だけ読み取る
  static vector<long long> ReadInts(long long number) {
    vector<long long> a(number);
    for (int i = 0; i < number; i++) {
      std::cin >> a[i];
    }

    return a;
  }

  // 渡された自然数が素数ならtureを返す
  static bool PrimeCheck_Int(long long number) {
    if (number < 2)
      return false;

    for (ULL i = 2; i * i <= number; i++) {
      if (number % i == 0)
        return false;
    }

    return true;
  }

  // 渡された数値以下の素数表を作る
  static vector<long long> MakePrimeList(long long n) {
    vector<long long> list;
    LL i, j, p;
    bool flag;
    for (i = 2; i <= n; i++) {
      flag = true;
      for (j = 0; j < list.size(); j++) {

        if (!(list[j] * list[j] <= i))
          break;

        if (i % list[j] == 0) {
          flag = false;
          break;
        }
      }
      if (flag)
        list.push_back(i);
    }

    return list;
  }

  // 文字列の分割
  static vector<string> split(string const &str, char sep) {
    vector<std::string> v;    // 分割結果を格納するベクター
    auto first = str.begin(); // テキストの最初を指すイテレータ
    while (first != str.end()) { // テキストが残っている間ループ
      auto last = first;         // 分割文字列末尾へのイテレータ
      while (last != str.end() &&
             *last != sep) // 末尾 or セパレータ文字まで進める
        last++;
      v.push_back(string(first, last)); // 分割文字を出力
      if (last != str.end())
        last++;
      first = last; // 次の処理のためにイテレータを設定
    }
    return v;
  }

  // 合計を求める
  static LL Sum(vector<LL> a) {
    LL i, sum = 0;

    for (i = 0; i < a.size(); i++) {
      sum += a[i];
    }

    return sum;
  }

  // 小文字ならtrueを返す
  static bool Komoji(char a) {
    if (a >= 'a' && a <= 'z')
      return true;

    return false;
  }

  // 大文字ならtrueを返す
  static bool Oomoji(char a) {
    if (a >= 'A' && a <= 'Z')
      return true;

    return false;
  }

  // 切り上げの整数値割り算
  static LL KiriageWarizan(LL a, LL b) {
    LL result = a / b;

    if (a % b > 0)
      result++;

    return result;
  }

  // 最大公約数
  static LL GreatestCommonFactor(LL a, LL b) {
    LL temp;
    if (a < b) {
      temp = b;
      b = a;
      a = temp;
    }

    while (true) {
      temp = a % b;
      a = b;
      b = temp;
      if (b == 0)
        break;
    }

    return a;
  }

  // 最小公倍数
  static LL LeastCommonMultiple(LL a, LL b) {
    return (a / GreatestCommonFactor(a, b)) * b;
  }

  // 素因数分解
  static vector<VLL> PrimeFactorization(LL n) {
    VLL p_list, s_list;

    LL i, j, k, count;

    for (i = 2; n > 1; i++) {
      if (i * i > n) {
        p_list.push_back(n);
        s_list.push_back(1);
        break;
      }

      if (n % i == 0) {
        count = 0;
        while (n % i == 0) {
          n /= i;
          count++;
        }

        p_list.push_back(i);
        s_list.push_back(count);
      }
    }

    vector<VLL> result;
    result.push_back(p_list);
    result.push_back(s_list);

    return result;
  }

  // 組み合わせ nCr
  static LL Combination(LL n, LL r) {
    r = min(r, n - r);

    VLL p(n + 1, 0);

    LL i, j, k, a, b, c;

    for (i = 1; i <= r; i++) {
      auto temp = MYCP::PrimeFactorization(i);

      for (j = 0; j < temp[0].size(); j++) {
        p[temp[0][j]] -= temp[1][j];
      }

      a = i + n - r;
      temp = MYCP::PrimeFactorization(a);

      for (j = 0; j < temp[0].size(); j++) {
        p[temp[0][j]] += temp[1][j];
      }
    }

    LL result = 1;

    for (i = 0; i < p.size(); i++) {
      if (p[i] > 0) {

        for (j = 0; j < p[i]; j++) {
          result *= i;
          result %= MYCP::MOD_CONST_ATCODER;
        }
      }
    }

    return result;
  }

  // 符号
  static LL sign(LL const x) {
    if (x > 0)
      return 1;
    if (x < 0)
      return -1;
    return 0;
  }

  // 円周率
  static double PI() { return (double)3.1415926535898; }

  // 指定した桁でdoubleを出す
  static void CoutDoubleKeta(double a, LL keta) {
    cout << setprecision(keta) << a << flush;
  }

  // 数値の出力
  static void CoutVectorLL(VLL list) {
    LL i, j, k, n;
    n = list.size();

    for (i = 0; i < n - 1; i++) {
      cout << list[i] << " ";
    }

    cout << list[n - 1] << flush;
  }

  // VLLの配列をソートする
  static void Sort_VLL(VVLL &x, LL n) {
    auto function = [&](VLL a, VLL b) { return a[n] < b[n]; };

    sort(x.begin(), x.end(), function);
  }

  // デバッグ用出力
  static LL DebugPrintf(string output) {

    if (MYCP::DebugFlag) {
      std::cout << output << endl;
    }

    return MYCP::DebugFlag;
  }

  // デバッグ用入力
  static LL DebugCin() {
    LL a;

    if (MYCP::DebugFlag) {
      cin >> a;
    }

    return a;
  }
};
LL MYCP::DebugFlag = 0;

// 累積和を求めるクラス
class Ruisekiwa {
private:
  vector<LL> list;

public:
  void MakeArray(vector<LL> data) {
    LL i;
    list = data;
    list.push_back(0);
    list[0] = 0;
    for (i = 1; i < list.size(); i++) {
      list[i] = list[i - 1] + data[i - 1];
    }
  }

  LL Sum(LL start, LL end) {
    if (end < start) {
      std::cout << "startがendより大きいです";
      return 0;
    }
    if (start < 0 || end >= list.size()) {
      std::cout << "範囲が異常";
      return 0;
    }

    return list[end] - list[start];
  }
};

// n進数を管理するクラス
class N_Number {
public:
  N_Number(LL n, LL keta) {
    this->N_Shinsuu = n;

    VLL temp(keta, 0);
    this->numbers = temp;
  }

  // 数を足す
  void plus(LL a) {
    if (a < 0) {
      a *= (-1);
      this->minus(a);
      return;
    }

    this->numbers[0] += a;
    LL size = this->numbers.size();
    for (LL i = 0; i < size; i++) {
      if (i + 1 < size) {
        this->numbers[i + 1] += this->numbers[i] / this->N_Shinsuu;
      }
      this->numbers[i] %= this->N_Shinsuu;
    }
  }

  // 全ての桁が同じ数字になっていればその数字を返す。それ以外の場合は -1 を返す
  LL check() {
    LL a = this->numbers[0];

    for (LL i = 0; i < this->numbers.size(); i++) {
      if (this->numbers[i] != a)
        return -1;
    }

    return a;
  }

  LL getNumber(LL keta) { return this->numbers[keta]; }

  LL getKeta() { return this->numbers.size(); }

  LL getShinsuu() { return this->N_Shinsuu; }

  void setNumber(LL keta, LL number) {
    if (0 <= number && number < this->getShinsuu()) {
      if (0 <= keta && keta < this->getKeta()) {
        this->numbers[keta] = number;
        return;
      }
    }

    cout << "er" << endl;
  }

  void setAllNumbers(LL number) {
    LL size = this->getKeta(), i;
    for (i = 0; i < size; i++) {
      this->setNumber(i, number);
    }
  }

  string to_string_KetaSoroe() {
    string s = "";
    for (LL i = this->getKeta() - 1; i >= 0; i--) {
      s += to_string(this->getNumber(i));
    }

    return s;
  }

private:
  void minus(LL a) {
    LL i, j, k, zettaiti = abs(a);

    k = MYCP::KiriageWarizan(zettaiti, this->N_Shinsuu);
    j = k * (this->N_Shinsuu - 1);

    for (i = 0; i < this->getKeta(); i++) {
      this->numbers[i] += j;
    }

    this->numbers[0] += k - a;
    this->plus(0);
  }

  VLL numbers;
  LL N_Shinsuu;
};

// UnionFind
class Union_Find {
private:
  VLL tree;
  VLL count;

  LL root(LL a) {
    if (this->tree[a] == a)
      return a;
    return this->tree[a] = this->root(this->tree[a]);
  }

public:
  Union_Find(LL n) {
    VLL set(n);
    this->tree = set;
    this->count = set;

    for (LL i = 0; i < n; i++) {
      this->tree[i] = i;
      this->count[i] = 1;
    }
  }

  void unite(LL a, LL b) {
    LL x, y;

    if (!this->Check(a, b)) {
      x = this->getCount(a) + getCount(b);

      y = this->root(a);
      this->count[y] = x;

      y = this->root(b);
      this->count[y] = x;
    }

    x = this->root(a);
    y = this->root(b);

    this->tree[x] = y;
  }

  bool Check(LL a, LL b) { return this->root(a) == this->root(b); }

  LL getCount(LL index) {
    LL temp = this->root(index);
    return this->count[temp];
  }
};

// プラスマイナス無限に対応したlong long型
class INF_LONG_LONG {
private:
  LL inf, n;

public:
  // コンストラクタ
  INF_LONG_LONG(LL a) {
    this->n = a;
    this->inf = 0;

    this->Syusei();
  }

  INF_LONG_LONG() { *this = INF_LONG_LONG(0); }

  INF_LONG_LONG(INF_LONG_LONG const &a) {
    this->n = a.n;
    this->inf = a.inf;

    this->Syusei();
  }

  // ゲッター
  LL getN() const { return this->n; }

  LL getInf() const { return this->inf; }

  // 正の無限大生成
  static INF_LONG_LONG plus_inf() {
    INF_LONG_LONG a;
    a.n = 0;
    a.inf = 1;

    a.Syusei();

    return a;
  }

  // 負の無限大生成
  static INF_LONG_LONG minus_inf() {
    INF_LONG_LONG a;
    a.n = 0;
    a.inf = -1;

    a.Syusei();

    return a;
  }

  // 符号を取得
  LL sign() const {
    if (this->inf != 0) {
      return this->inf;
    }

    return MYCP::sign(this->n);
  }

  // 代入演算子
  INF_LONG_LONG operator=(INF_LONG_LONG const &b) {
    this->n = b.n;
    this->inf = b.inf;

    this->Syusei();

    return *this;
  }

  INF_LONG_LONG operator=(LL const &b) {
    *this = INF_LONG_LONG(b);

    this->Syusei();

    return *this;
  }

  // 比較演算子
  bool operator==(INF_LONG_LONG const &b) const {
    if (this->n == b.n && this->inf == b.inf)
      return true;

    return false;
  }

  bool operator!=(INF_LONG_LONG const &b) const { return !(*this == b); }

  bool operator<(INF_LONG_LONG const &b) const {
    if (this->inf < b.inf)
      return true;

    if (this->inf > b.inf)
      return false;

    return this->n < b.n;
  }

  bool operator>(INF_LONG_LONG const &b) const { return b < *this; }

  bool operator<=(INF_LONG_LONG const &b) const { return !(*this > b); }

  bool operator>=(INF_LONG_LONG const &b) const { return !(*this < b); }

  // 算術演算子
  INF_LONG_LONG operator+(INF_LONG_LONG const &b) const {
    if (max(this->inf, b.inf) > 0)
      return INF_LONG_LONG::plus_inf();
    if (min(this->inf, b.inf) < 0)
      return INF_LONG_LONG::minus_inf();

    auto ans = *this;
    ans.n += b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator*(INF_LONG_LONG const &b) const {

    if (*this == INF_LONG_LONG(0) || b == INF_LONG_LONG(0)) {
      return INF_LONG_LONG(0);
    }

    if (this->inf != 0 || b.inf != 0) {
      LL s = this->sign() * b.sign();

      INF_LONG_LONG ans(0);
      ans.n = 0;
      ans.inf = s;

      ans.Syusei();

      return ans;
    }

    INF_LONG_LONG ans(0);

    ans.n = this->n * b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator-(INF_LONG_LONG const &b) const {
    auto ans = (*this + (INF_LONG_LONG(-1) * b));
    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator/(INF_LONG_LONG const &b) const {
    if (b == INF_LONG_LONG(0)) {
      LL a = this->n / b.n;

      return INF_LONG_LONG(a);
    }

    if (b.inf != 0) {
      return INF_LONG_LONG(0);
    }

    if (*this == INF_LONG_LONG(0)) {
      return INF_LONG_LONG(0);
    }

    if (this->inf != 0) {
      LL s = this->sign() * b.sign();

      return INF_LONG_LONG::plus_inf() * INF_LONG_LONG(s);
    }

    INF_LONG_LONG ans;

    ans.n = this->n / b.n;

    ans.Syusei();

    return ans;
  }

  INF_LONG_LONG operator%(INF_LONG_LONG const &b) const {
    if (this->inf == 0 && b.inf == 0) {
      INF_LONG_LONG ans;

      ans.n = this->n % b.n;

      ans.Syusei();

      return ans;
    }

    auto x = *this / b;
    x.Syusei();
    auto ans = *this - b * x;
    ans.Syusei();

    return ans;
  }

  // 複合代入演算子
  INF_LONG_LONG operator+=(INF_LONG_LONG const &b) {
    auto ans = *this + b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator-=(INF_LONG_LONG const &b) {
    auto ans = *this - b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator*=(INF_LONG_LONG const &b) {
    auto ans = *this * b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator/=(INF_LONG_LONG const &b) {
    auto ans = *this / b;
    *this = ans;

    return *this;
  }

  INF_LONG_LONG operator%=(INF_LONG_LONG const &b) {
    auto ans = *this % b;
    *this = ans;

    return *this;
  }

  // 符号演算子
  INF_LONG_LONG operator+() const { return *this; }

  INF_LONG_LONG operator-() const { return *this * INF_LONG_LONG(-1); }

  // 前置きインクリメント・デクリメント
  INF_LONG_LONG operator++() {
    this->n++;
    this->Syusei();

    return *this;
  }

  INF_LONG_LONG operator--() {
    this->n--;
    this->Syusei();

    return *this;
  }

  // 後置きインクリメント・デクリメント
  INF_LONG_LONG operator++(int) {
    auto copy = *this;
    ++(*this);
    return copy;
  }

  INF_LONG_LONG operator--(int) {
    auto copy = *this;
    --(*this);
    return copy;
  }

  // 文字列への変換
  string ToString() const {
    if (this->inf == 1) {
      return "+INF";
    }

    if (this->inf == -1) {
      return "-INF";
    }

    return to_string(this->n);
  }

private:
  void Syusei() {
    if (this->inf != 0) {
      this->n = 0;
    }
  }
};
typedef INF_LONG_LONG ILL_TYPE;
typedef vector<ILL_TYPE> VILL_TYPE;
typedef vector<VILL_TYPE> VVILL_TYPE;

// ワーシャルフロイド
class WarshallFloyd {
public:
  // 最短距離を記録
  VVILL_TYPE d;

  // 頂点数
  LL v;

  // vは頂点数、edge_cost_listは辺の情報{始点、終点、コスト}の配列。無向グラフの場合、逆矢印の辺に注意。
  WarshallFloyd(LL v, VVLL edge_cost_list) {
    this->v = v;

    this->d = VVILL_TYPE(v, VILL_TYPE(v, ILL_TYPE::plus_inf()));

    LL i, j, k, a, b, c;

    for (i = 0; i < edge_cost_list.size(); i++) {
      a = edge_cost_list[i][0];
      b = edge_cost_list[i][1];
      c = edge_cost_list[i][2];

      this->d[a][b] = ILL_TYPE(c);
    }

    for (i = 0; i < v; i++) {
      this->d[i][i] = ILL_TYPE(0);
    }

    // ここから計算
    for (k = 0; k < v; k++) {
      for (i = 0; i < v; i++) {
        for (j = 0; j < v; j++) {
          d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
        }
      }
    }
  }
};

// ベルマンフォード
class BellmanFord {
public:
  // 辺のリスト
  VVILL_TYPE edge;

  // 頂点数、辺数
  LL v, e;

  // 始点
  LL s;

  // 最短距離
  VILL_TYPE d;

  // vは頂点数、startは始点、edge_cost_listは辺の情報{始点、終点、コスト}の配列。
  BellmanFord(LL v, LL start, VVLL edge_cost_list) {
    this->v = v;
    this->s = start;
    this->e = edge_cost_list.size();
    this->d = VILL_TYPE(v, ILL_TYPE::plus_inf());
    this->d[start] = 0;

    LL i, j, k;
    for (i = 0; i < this->e; i++) {
      VILL_TYPE temp;
      LL a, b, c;
      a = edge_cost_list[i][0];
      b = edge_cost_list[i][1];
      c = edge_cost_list[i][2];

      temp.push_back(ILL_TYPE(a));
      temp.push_back(ILL_TYPE(b));
      temp.push_back(ILL_TYPE(c));

      this->edge.push_back(temp);
    }

    for (i = 0; i < v; i++) {
      bool update = true;

      for (j = 0; j < this->e; j++) {
        ILL_TYPE c;
        LL a, b;
        a = this->edge[j][0].getN();
        b = this->edge[j][1].getN();
        c = this->edge[j][2];

        if (this->d[a] < ILL_TYPE::plus_inf()) {
          if (this->d[a] + c < this->d[b]) {
            update = false;

            this->d[b] = this->d[a] + c;
          }
        }
      }

      if (update)
        break;
    }
  }
};

// ここからメイン
int main(void) {
  MYCP::DebugFlag = 0;

  LL i, j, k, n, m;
  cin >> n;

  vector<VVILL_TYPE> edge(n);

  for (i = 0; i < n - 1; i++) {
    auto temp = MYCP::ReadInts(3);
    temp[0]--;
    temp[1]--;

    VILL_TYPE a;
    a.push_back(ILL_TYPE(temp[1]));
    a.push_back(ILL_TYPE(temp[2]));

    edge[temp[0]].push_back(a);

    swap(temp[0], temp[1]);
    VILL_TYPE reset;
    a = reset;
    a.push_back(ILL_TYPE(temp[1]));
    a.push_back(ILL_TYPE(temp[2]));

    edge[temp[0]].push_back(a);
  }

  LL q;
  cin >> q >> k;
  k--;

  VLL x, y(q);
  x = y;
  for (i = 0; i < q; i++) {
    cin >> x[i] >> y[i];
    x[i]--;
    y[i]--;
  }

  VILL_TYPE d(n, ILL_TYPE::plus_inf());
  d[k] = 0;

  list<LL> ls;
  ls.push_back(k);

  LL count = 0;

  while (!ls.empty()) {
    count++;

    auto itr = ls.begin();

    for (i = 0; i < edge[*itr].size(); i++) {
      auto a = edge[*itr][i][0].getN();
      auto b = edge[*itr][i][1];

      if (d[*itr] + b < d[a]) {
        d[a] = d[*itr] + b;

        ls.push_back(a);
      }
    }

    ls.pop_front();
  }

  MYCP::DebugPrintf(to_string(count));

  for (i = 0; i < n; i++) {
    string temp = to_string(i) + ":" + to_string(d[i].getN());

    if (d[i].getInf())
      MYCP::DebugPrintf("無限");
    else
      MYCP::DebugPrintf(temp);
  }

  MYCP::DebugPrintf("ここまで");

  for (i = 0; i < q; i++) {
    cout << (d[x[i]] + d[y[i]]).getN() << endl;
  }

  return 0;
}