Problem p02587 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef pair<pii, pii> pippi;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1LL << 61;
int iinf = 1 << 30;
double pi = 3.14159265358979323846;
double pi2 = pi / 2.0;
double eps = 1e-8;
#define rep(i, m, n) for (ll i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto &itr : mp)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
// #define endl "\\n"
int dh[4] = {1, 0, -1, 0};
int dw[4] = {0, 1, 0, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }

  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
#define umh unordered_map<int, int, custom_hash>
ll gcd(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  if (k < 0)
    return 0;
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ll n;
  cin >> n;
  string s[n];
  ll c[n];
  rep(i, 0, n) cin >> s[i] >> c[i];
  map<pair<string, int>, ll> mp;
  rep(i, 0, n) {
    rep(j, 0, s[i].size() + 1) {
      string a = s[i].substr(0, j);
      string b = s[i].substr(j);
      int x = min(a.size(), b.size());
      reverse(a.begin(), a.end());
      if (a.substr(0, x) == b.substr(0, x)) {
        if (a.size() > b.size()) {
          string d = a.substr(x);
          reverse(d.begin(), d.end());
          if (mp.count({d, 0}) == 0)
            mp[{d, 0}] = c[i];
          else
            mp[{d, 0}] = min(mp[{d, 0}], c[i]);
        } else {
          string d = b.substr(x);
          if (mp.count({d, 1}) == 0)
            mp[{d, 1}] = c[i];
          else
            mp[{d, 1}] = min(mp[{d, 1}], c[i]);
        }
      }
      if (j == s[i].size())
        break;
      a = s[i].substr(0, j);
      b.erase(b.begin());
      x = min(a.size(), b.size());
      reverse(a.begin(), a.end());
      if (a.substr(0, x) == b.substr(0, x)) {
        if (a.size() > b.size()) {
          string d = a.substr(x);
          reverse(d.begin(), d.end());
          if (mp.count({d, 0}) == 0)
            mp[{d, 0}] = c[i];
          else
            mp[{d, 0}] = min(mp[{d, 0}], c[i]);
        } else {
          string d = b.substr(x);
          if (mp.count({d, 1}) == 0)
            mp[{d, 1}] = c[i];
          else
            mp[{d, 1}] = min(mp[{d, 1}], c[i]);
        }
      }
    }
  }
  typedef pair<ll, pair<string, int>> P;
  priority_queue<P, vector<P>, greater<P>> q;
  mrep(p, mp) { q.push({p.second, p.first}); }
  while (q.size() > 0) {
    P p = q.top();
    q.pop();
    string now = p.second.first;
    int ty = p.second.second;
    ll dis = p.first;
    if (mp[{now, ty}] < dis)
      continue;
    if (now == "") {
      cout << dis << endl;
      return 0;
    }
    if (ty == 0) {
      rep(i, 0, n) {
        string a = now;
        string b = s[i];
        reverse(a.begin(), a.end());
        int x = min(b.size(), a.size());
        if (a.substr(0, x) == b.substr(0, x)) {
          if (a.size() > b.size()) {
            string d = a.substr(x);
            reverse(d.begin(), d.end());
            if (mp.count({d, 0}) == 0) {
              mp[{d, 0}] = c[i] + dis;
              q.push({c[i] + dis, {d, 0}});
            } else if (mp[{d, 0}] > dis + c[i]) {
              mp[{d, 0}] = c[i] + dis;
              q.push({c[i] + dis, {d, 0}});
            }
          } else {
            string d = b.substr(x);
            if (mp.count({d, 1}) == 0) {
              mp[{d, 1}] = c[i] + dis;
              q.push({c[i] + dis, {d, 1}});
            } else if (mp[{d, 1}] > dis + c[i]) {
              mp[{d, 1}] = c[i] + dis;
              q.push({c[i] + dis, {d, 1}});
            }
          }
        }
      }
    } else {
      rep(i, 0, n) {
        string a = s[i];
        string b = now;
        reverse(a.begin(), a.end());
        int x = min(b.size(), a.size());
        if (a.substr(0, x) == b.substr(0, x)) {
          if (a.size() > b.size()) {
            string d = a.substr(x);
            reverse(d.begin(), d.end());
            if (mp.count({d, 0}) == 0) {
              mp[{d, 0}] = c[i] + dis;
              q.push({c[i] + dis, {d, 0}});
            } else if (mp[{d, 0}] > dis + c[i]) {
              mp[{d, 0}] = c[i] + dis;
              q.push({c[i] + dis, {d, 0}});
            }
          } else {
            string d = b.substr(x);
            if (mp.count({d, 1}) == 0) {
              mp[{d, 1}] = c[i] + dis;
              q.push({c[i] + dis, {d, 1}});
            } else if (mp[{d, 1}] > dis + c[i]) {
              mp[{d, 1}] = c[i] + dis;
              q.push({c[i] + dis, {d, 1}});
            }
          }
        }
      }
    }
  }
  cout << -1 << endl;
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef pair<pii, pii> pippi;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1LL << 61;
int iinf = 1 << 30;
double pi = 3.14159265358979323846;
double pi2 = pi / 2.0;
double eps = 1e-8;
#define rep(i, m, n) for (int i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto &itr : mp)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
// #define endl "\\n"
int dh[4] = {1, 0, -1, 0};
int dw[4] = {0, 1, 0, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }

  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
#define umh unordered_map<int, int, custom_hash>
ll gcd(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  if (k < 0)
    return 0;
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}
int n;
string s[50], t[50];
ll c[50];
ll ans = inf;
vector<int> v[50][2][20];
int bo;
ll ha[50][2];
ll mo[25];
void dfs(int ns, int nt, int num, int ba, ll sums, ll sumt, ll has, ll hat) {
  if (ns == nt) {
    if (has == hat)
      Min(ans, min(sums, sumt));
    else
      Min(ans, sums + sumt);
  }
  if (ns > 2000 && nt > 2000)
    return;
  if (ns > nt)
    bo = 0;
  else
    bo = 1;
  rep(i, 0, v[num][bo][ba].size()) {
    int ne = v[num][bo][ba][i];
    if (bo == 0) {
      if (t[ne].size() + nt <= ns) {
        dfs(ns, nt + t[ne].size(), num, ba + t[ne].size(), sums, sumt + c[ne],
            has, (hat * mo[t[ne].size()] + ha[ne][0]) % 10007);
      } else {
        dfs(ns, nt + t[ne].size(), ne, ns - nt, sums, sumt + c[ne], has,
            (hat * mo[t[ne].size()] + ha[ne][0]) % 10007);
      }
    } else {
      if (s[ne].size() + ns <= nt) {
        dfs(ns + s[ne].size(), nt, num, ba + s[ne].size(), sums + c[ne], sumt,
            (has * mo[s[ne].size()] + ha[ne][0]) % 10007, hat);
      } else {
        dfs(ns + s[ne].size(), nt, ne, nt - ns, sums + c[ne], sumt,
            (has * mo[s[ne].size()] + ha[ne][0]) % 10007, hat);
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  rep(i, 0, n) {
    cin >> s[i] >> c[i];
    t[i] = s[i];
    reverse(t[i].begin(), t[i].end());
    ha[i][0] = 0;
    rep(j, 0, s[i].size()) {
      ha[i][0] *= mod;
      ha[i][0] += s[i][j];
      ha[i][0] %= 10007;
    }
    rep(j, 0, t[i].size()) {
      ha[i][1] *= mod;
      ha[i][1] += t[i][j];
      ha[i][1] %= 10007;
    }
  }
  rep(i, 0, 25) { mo[i] = beki(mod, i, 10007); }
  rep(i, 0, n) {
    rep(j, 0, s[i].size()) {
      string now = s[i].substr(j);
      rep(k, 0, n) {
        bool boo = true;
        rep(l, 0, t[k].size()) {
          if (l == now.size())
            break;
          if (t[k][l] != now[l]) {
            boo = false;
            break;
          }
        }
        if (boo)
          v[i][0][j].push_back(k);
      }
      now = t[i].substr(j);
      rep(k, 0, n) {
        bool boo = true;
        rep(l, 0, s[k].size()) {
          if (l == now.size())
            break;
          if (s[k][l] != now[l]) {
            boo = false;
            break;
          }
        }
        if (boo)
          v[i][1][j].push_back(k);
      }
    }
  }
  rep(i, 0, n) { dfs(s[i].size(), 0, i, 0, c[i], 0, ha[i][0], 0); }
  if (ans == inf)
    ans = -1;
  cout << ans << endl;
}