Problem p01275 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
typedef long long ll;
typedef ll li;
typedef pair<int, int> PI;
#define EPS (1e-6)
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define REP(i, n) rep(i, n)
#define F first
#define S second
#define mp(a, b) make_pair(a, b)
#define pb(a) push_back(a)
#define min3(a, b, c) min((a), min((b), (c)))
#define min4(a, b, c, d) min((a), min3((b), (c), (d)))
#define SZ(a) (int)((a).size())
#define ALL(a) a.begin(), a.end()
#define FLL(a, b) memset((a), b, sizeof(a))
#define CLR(a) memset((a), 0, sizeof(a))
#define FOR(it, a) for (__typeof(a.begin()) it = a.begin(); it != a.end(); ++it)
template <typename T, typename U>
ostream &operator<<(ostream &out, const pair<T, U> &val) {
  return out << "(" << val.F << ", " << val.S << ")";
}
template <class T> ostream &operator<<(ostream &out, const vector<T> &val) {
  out << "{";
  rep(i, SZ(val)) out << (i ? ", " : "") << val[i];
  return out << "}";
}
typedef double FP;
typedef complex<FP> pt;
typedef pt P;
typedef pair<pt, pt> line;
FP dot(P a, P b) { return real(conj(a) * b); }
FP crs(P a, P b) { return imag(conj(a) * b); }
P ortho(P a) { return P(imag(a), -real(a)); }
P ortho(line a) { return ortho(a.S - a.F); }
P crspt(P a, P b, P c, P d) {
  b -= a, d -= c;
  return a + b * crs(d, c - a) / crs(d, b);
}
P crspt(line a, line b) { return crspt(a.F, a.S, b.F, b.S); }
bool onl(P a1, P a2, P b) {
  return abs(b - a1) + abs(b - a2) < abs(a1 - a2) + EPS;
}
bool onl(line a, P b) { return onl(a.F, a.S, b); }
bool iscrs(line a, line b) {
  P c = crspt(a, b);
  return onl(a, c) && onl(b, c);
}
void pkuassert(bool t) { t = 1 / t; };
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1};
int dy[] = {1, 0, -1, 0, -1, 1, 1, -1};
enum { TOP, BTM, LFT, RGT, FRT, BCK };
int dxdy2ce[] = {RGT, FRT, LFT, BCK};
int s2i(string &a) {
  stringstream ss(a);
  int r;
  ss >> r;
  return r;
}
template <class T> T shift(T a, int b, int c, int d, int e) {
  __typeof(a[0]) t = a[b];
  a[b] = a[c];
  a[c] = a[d];
  a[d] = a[e];
  a[e] = t;
  return a;
}
template <class T> T rgt(T a) { return shift(a, TOP, LFT, BTM, RGT); }
template <class T> T lft(T a) { return shift(a, TOP, RGT, BTM, LFT); }
template <class T> T frt(T a) { return shift(a, TOP, BCK, BTM, FRT); }
template <class T> T bck(T a) { return shift(a, TOP, FRT, BTM, BCK); }
line mkl(P a, P v) { return line(a, a + v); }
FP lpdist(line a, P b) { return abs(b - crspt(a, mkl(b, ortho(a)))); }
FP spdist(line a, P b) {
  P c(crspt(a, mkl(b, ortho(a))));
  return onl(a, c) ? abs(b - c) : min(abs(a.F - b), abs(a.S - b));
}
FP ssdist(line a, line b) {
  return iscrs(a, b) ? 0.
                     : min4(spdist(a, b.F), spdist(a, b.S), spdist(b, a.F),
                            spdist(b, a.S));
}

void solve() {
  string a, b;
  cin >> a >> b;
  set<string> vis;
  queue<pair<int, string>> q;
  q.push(mp(0, a));
  while (!q.empty()) {
    int cc = q.front().F;
    string cv = q.front().S;
    q.pop();
    if (vis.count(cv))
      continue;
    if (cv == b) {
      cout << cc << endl;
      return;
    }
    vis.insert(cv);
    rep(i, SZ(cv)) {
      if (cv[i] == b[i])
        continue;
      for (int j = i; j < SZ(cv); ++j) {
        rep(k, 10) {
          string ne(cv);
          for (int t = i; t <= j; ++t)
            ne[t] = (ne[t] - '0' + k) % 10 + '0';
          if (ne[i] == b[i])
            q.push(mp(cc + 1, ne));
        }
      }
      break;
    }
  }
}

int main(int argc, char *argv[]) {
  int n;
  while (cin >> n && n)
    solve();
  return 0;
}

Error: 0

Fixed submission:

#include <algorithm>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
typedef long long ll;
typedef ll li;
typedef pair<int, int> PI;
#define EPS (1e-6)
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define REP(i, n) rep(i, n)
#define F first
#define S second
#define mp(a, b) make_pair(a, b)
#define pb(a) push_back(a)
#define min3(a, b, c) min((a), min((b), (c)))
#define min4(a, b, c, d) min((a), min3((b), (c), (d)))
#define SZ(a) (int)((a).size())
#define ALL(a) a.begin(), a.end()
#define FLL(a, b) memset((a), b, sizeof(a))
#define CLR(a) memset((a), 0, sizeof(a))
#define FOR(it, a) for (__typeof(a.begin()) it = a.begin(); it != a.end(); ++it)
template <typename T, typename U>
ostream &operator<<(ostream &out, const pair<T, U> &val) {
  return out << "(" << val.F << ", " << val.S << ")";
}
template <class T> ostream &operator<<(ostream &out, const vector<T> &val) {
  out << "{";
  rep(i, SZ(val)) out << (i ? ", " : "") << val[i];
  return out << "}";
}
typedef double FP;
typedef complex<FP> pt;
typedef pt P;
typedef pair<pt, pt> line;
FP dot(P a, P b) { return real(conj(a) * b); }
FP crs(P a, P b) { return imag(conj(a) * b); }
P ortho(P a) { return P(imag(a), -real(a)); }
P ortho(line a) { return ortho(a.S - a.F); }
P crspt(P a, P b, P c, P d) {
  b -= a, d -= c;
  return a + b * crs(d, c - a) / crs(d, b);
}
P crspt(line a, line b) { return crspt(a.F, a.S, b.F, b.S); }
bool onl(P a1, P a2, P b) {
  return abs(b - a1) + abs(b - a2) < abs(a1 - a2) + EPS;
}
bool onl(line a, P b) { return onl(a.F, a.S, b); }
bool iscrs(line a, line b) {
  P c = crspt(a, b);
  return onl(a, c) && onl(b, c);
}
void pkuassert(bool t) { t = 1 / t; };
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1};
int dy[] = {1, 0, -1, 0, -1, 1, 1, -1};
enum { TOP, BTM, LFT, RGT, FRT, BCK };
int dxdy2ce[] = {RGT, FRT, LFT, BCK};
int s2i(string &a) {
  stringstream ss(a);
  int r;
  ss >> r;
  return r;
}
template <class T> T shift(T a, int b, int c, int d, int e) {
  __typeof(a[0]) t = a[b];
  a[b] = a[c];
  a[c] = a[d];
  a[d] = a[e];
  a[e] = t;
  return a;
}
template <class T> T rgt(T a) { return shift(a, TOP, LFT, BTM, RGT); }
template <class T> T lft(T a) { return shift(a, TOP, RGT, BTM, LFT); }
template <class T> T frt(T a) { return shift(a, TOP, BCK, BTM, FRT); }
template <class T> T bck(T a) { return shift(a, TOP, FRT, BTM, BCK); }
line mkl(P a, P v) { return line(a, a + v); }
FP lpdist(line a, P b) { return abs(b - crspt(a, mkl(b, ortho(a)))); }
FP spdist(line a, P b) {
  P c(crspt(a, mkl(b, ortho(a))));
  return onl(a, c) ? abs(b - c) : min(abs(a.F - b), abs(a.S - b));
}
FP ssdist(line a, line b) {
  return iscrs(a, b) ? 0.
                     : min4(spdist(a, b.F), spdist(a, b.S), spdist(b, a.F),
                            spdist(b, a.S));
}

void solve() {
  string a, b;
  cin >> a >> b;
  set<string> vis;
  queue<pair<int, string>> q;
  q.push(mp(0, a));
  while (!q.empty()) {
    int cc = q.front().F;
    string cv = q.front().S;
    q.pop();
    if (vis.count(cv))
      continue;
    if (cv == b) {
      cout << cc << endl;
      return;
    }
    vis.insert(cv);
    bool ok = true;
    rep(i, SZ(cv)) {
      if (ok && cv[i] == b[i])
        continue;
      ok = false;
      for (int j = i; j < SZ(cv); ++j) {
        rep(k, 9) {
          string ne(cv);
          for (int t = i; t <= j; ++t)
            ne[t] = (ne[t] - '0' + k) % 10 + '0';
          q.push(mp(cc + 1, ne));
        }
      }
      break;
    }
  }
}

int main(int argc, char *argv[]) {
  int n;
  while (cin >> n && n)
    solve();
  return 0;
}