Problem p04017 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <bitset>
#include <complex>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <istream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> vec;
typedef vector<vec> mat;
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define revrep(i, n) for (ll i = (n - 1); i >= 0; i--)
#define pb push_back
#define f first
#define s second
ll max(ll a, ll b) { return (a > b) ? a : b; }
ll min(ll a, ll b) { return (a < b) ? a : b; }
ll max3(ll a, ll b, ll c) { return max(a, max(b, c)); };
ll min3(ll a, ll b, ll c) { return min(a, min(b, c)); };
ll max4(ll a, ll b, ll c, ll d) { return max(max(a, b), min(c, d)); };
ll min4(ll a, ll b, ll c, ll d) { return min(min(a, b), min(c, d)); };
ll max5(ll a, ll b, ll c, ll d, ll e) { return max(max(a, b), max3(c, d, e)); };
ll min5(ll a, ll b, ll c, ll d, ll e) { return min(min(a, b), min3(c, d, e)); };

const ll INFL = 1LL << 60; // 10^18 = 2^60
const int INF = 1 << 30;   // 10^9
ll MOD = 1000000007;
// ll MOD = 998244353;
vector<ll> dy = {0, 0, 1, -1, 1, 1, -1, -1, 0};
vector<ll> dx = {1, -1, 0, 0, 1, -1, 1, -1, 0};

ll pow_long(ll x, ll k) {
  ll res = 1;
  while (k > 0) {
    if (k % 2)
      res *= x;
    x *= x;
    k /= 2;
  }
  return res;
}
ll pow_mod(ll x, ll k) {
  x %= MOD;
  x += MOD;
  x %= MOD;
  ll res = 1;
  while (k > 0) {
    if (k % 2) {
      res *= x;
      res %= MOD;
    }
    x *= x;
    x %= MOD;
    k /= 2;
  }
  return res;
}

ll inverse(ll x) { return pow_mod(x, MOD - 2); };

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll x, ll y) { return x / gcd(x, y) * y; };

ll kai_mod(ll x) {
  if (x == 0)
    return 1;
  return x * kai_mod(x - 1) % MOD;
}

/*
//コンビネーション
const int MAXcomb = 200010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAXcomb; 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;
    }
}
ll comb(int n, int k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] % MOD * finv[n-k] % MOD;
}
*/
ll N, L, Q;
vector<ll> X(100010);
ll Next[100010][20];
int main() {
  cin >> N;
  X.resize(N);

  rep(i, N) cin >> X[i];
  X.pb(INFL);
  cin >> L;
  rep(i, N) {
    Next[i][0] = upper_bound(X.begin(), X.end(), X[i] + L) - X.begin() - 1;
  }

  for (ll j = 1; j < 20; j++) {
    rep(i, N) { Next[i][j] = Next[Next[i][j - 1]][j - 1]; }
  }

  cin >> Q;
  rep(i, Q) {
    ll a, b;
    cin >> a >> b;
    a--, b--;
    if (a > b)
      swap(a, b);
    ll now = a;
    ll cnt = 0;
    while (now != b) {
      if (Next[now][0] >= b) {
        cnt++;
        break;
      }
      rep(j, 20) {
        if (b < Next[now][j + 1]) {
          now = Next[now][j];
          cnt += pow_long(2, j);
          break;
        }
      }
    }
    cout << cnt << endl;
  }
}


Fixed submission:
#include <algorithm>
#include <bitset>
#include <complex>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <istream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> vec;
typedef vector<vec> mat;
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define revrep(i, n) for (ll i = (n - 1); i >= 0; i--)
#define pb push_back
#define f first
#define s second
ll max(ll a, ll b) { return (a > b) ? a : b; }
ll min(ll a, ll b) { return (a < b) ? a : b; }
ll max3(ll a, ll b, ll c) { return max(a, max(b, c)); };
ll min3(ll a, ll b, ll c) { return min(a, min(b, c)); };
ll max4(ll a, ll b, ll c, ll d) { return max(max(a, b), min(c, d)); };
ll min4(ll a, ll b, ll c, ll d) { return min(min(a, b), min(c, d)); };
ll max5(ll a, ll b, ll c, ll d, ll e) { return max(max(a, b), max3(c, d, e)); };
ll min5(ll a, ll b, ll c, ll d, ll e) { return min(min(a, b), min3(c, d, e)); };

const ll INFL = 1LL << 60; // 10^18 = 2^60
const int INF = 1 << 30;   // 10^9
ll MOD = 1000000007;
// ll MOD = 998244353;
vector<ll> dy = {0, 0, 1, -1, 1, 1, -1, -1, 0};
vector<ll> dx = {1, -1, 0, 0, 1, -1, 1, -1, 0};

ll pow_long(ll x, ll k) {
  ll res = 1;
  while (k > 0) {
    if (k % 2)
      res *= x;
    x *= x;
    k /= 2;
  }
  return res;
}
ll pow_mod(ll x, ll k) {
  x %= MOD;
  x += MOD;
  x %= MOD;
  ll res = 1;
  while (k > 0) {
    if (k % 2) {
      res *= x;
      res %= MOD;
    }
    x *= x;
    x %= MOD;
    k /= 2;
  }
  return res;
}

ll inverse(ll x) { return pow_mod(x, MOD - 2); };

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll x, ll y) { return x / gcd(x, y) * y; };

ll kai_mod(ll x) {
  if (x == 0)
    return 1;
  return x * kai_mod(x - 1) % MOD;
}

/*
//コンビネーション
const int MAXcomb = 200010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAXcomb; 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;
    }
}
ll comb(int n, int k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] % MOD * finv[n-k] % MOD;
}
*/
ll N, L, Q;
vector<ll> X(100010);
ll Next[100010][20];
int main() {
  cin >> N;
  X.resize(N);

  rep(i, N) cin >> X[i];
  X.pb(INFL);
  cin >> L;
  rep(i, N) {
    Next[i][0] = upper_bound(X.begin(), X.end(), X[i] + L) - X.begin() - 1;
  }

  for (ll j = 1; j < 20; j++) {
    rep(i, N) { Next[i][j] = Next[Next[i][j - 1]][j - 1]; }
  }

  cin >> Q;
  rep(i, Q) {
    ll a, b;
    cin >> a >> b;
    a--, b--;
    if (a > b)
      swap(a, b);
    ll now = a;
    ll cnt = 0;
    while (now != b) {
      if (Next[now][0] >= b) {
        cnt++;
        break;
      }
      rep(j, 20) {
        if (Next[now][j] >= b) {
          now = Next[now][j - 1];
          cnt += pow_long(2, j - 1);
          break;
        }
      }
    }
    cout << cnt << endl;
  }
}