Problem p00769 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <utility>
#include <vector>

using namespace std;

typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;

#define dump(x) cerr << #x << " = " << (x) << endl
#define rep(i, n) for (int i = 0; i < (n); i++)
#define REP(i, m, n) for (int i = (m); i < (n); i++)
#define ALL(a) (a).begin(), (a).end()
#define pb push_back
#define sz size()

string pre(string s) { // "][" を空白に置き換え
  string b = "";
  rep(i, s.sz - 1) {
    if (s[i] == ']' && s[i + 1] == '[') {
      b += ' ';
      i++;
    } else {
      b += s[i];
    }
  }
  b += s[s.sz - 1];
  return b;
}

string solve(int n, bool check, string s) {
  n++;
  string tmp[10000] = {};

  int count = 0;
  REP(j, n, s.sz) {
    if (s[j] != ']') {
      if (s[j] != ' ') {
        tmp[count] += s[j];
      } else {
        count++;
      }
    } else
      break;
  }
  vi a;
  rep(i, count + 1) { a.pb(stoi(tmp[i])); }
  sort(ALL(a));

  int sum = 0;
  rep(i, count / 2 + 1) {
    if (check == false)
      sum += a[i] / 2 + 1;
    else
      sum += a[i];
  }
  return to_string((sum));
}

string delSpace(string s) { // "] [" を "][" に置き換え
  string ret = "";
  rep(i, s.sz - 2) {
    if (s[i] == ']' && s[i + 1] == ' ' && s[i + 2] == '[') {
      ret += "][";
      i += 2;
    } else {
      ret += s[i];
    }
  }
  ret += s[s.sz - 2];
  ret += s[s.sz - 1];
  return ret;
}

int main() {
  int t;
  cin >> t;

  rep(times, t) {
    string s;
    cin >> s;
    int check = false;
    s = pre(s);
    while (1) {
      if (s.find("[", 0) == -1)
        break;

      string n = "";

      rep(i, s.sz) {
        if (s[i + 1] >= '0' && s[i + 1] <= '9') {
          n += solve(i, check, s);
          while (s[i] != ']')
            i++;
        } else {
          n += s[i];
        }
      }
      s = n;
      check = true;
    }
    cout << s << endl;
  }
  return 0;
}

Error: 0

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <utility>
#include <vector>

using namespace std;

typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;

#define dump(x) cerr << #x << " = " << (x) << endl
#define rep(i, n) for (int i = 0; i < (n); i++)
#define REP(i, m, n) for (int i = (m); i < (n); i++)
#define ALL(a) (a).begin(), (a).end()
#define pb push_back
#define sz size()

string pre(string s) { // "][" を空白に置き換え
  string b = "";
  rep(i, s.sz - 1) {
    if (s[i] == ']' && s[i + 1] == '[') {
      b += ' ';
      i++;
    } else {
      b += s[i];
    }
  }
  b += s[s.sz - 1];
  return b;
}

string solve(int n, bool check, string s) {
  n++;
  string tmp[100] = {};

  int count = 0;
  REP(j, n, s.sz) {
    if (s[j] != ']') {
      if (s[j] != ' ') {
        tmp[count] += s[j];
      } else {
        count++;
      }
    } else
      break;
  }
  vi a;
  rep(i, count + 1) { a.pb(stoi(tmp[i])); }
  sort(ALL(a));

  int sum = 0;
  rep(i, count / 2 + 1) {
    if (check == false)
      sum += a[i] / 2 + 1;
    else
      sum += a[i];
  }
  return to_string((sum));
}

string delSpace(string s) { // "] [" を "][" に置き換え
  string ret = "";
  rep(i, s.sz - 2) {
    if (s[i] == ']' && s[i + 1] == ' ' && s[i + 2] == '[') {
      ret += "][";
      i += 2;
    } else {
      ret += s[i];
    }
  }
  ret += s[s.sz - 2];
  ret += s[s.sz - 1];
  return ret;
}

int main() {
  int t;
  cin >> t;

  rep(times, t) {
    string s;
    cin >> s;
    int check = false;
    s = pre(s);
    while (1) {
      if (s.find("[", 0) == -1)
        break;

      string n = "";

      rep(i, s.sz) {
        if (s[i + 1] >= '0' && s[i + 1] <= '9') {
          n += solve(i, check, s);
          while (s[i] != ']')
            i++;
        } else {
          n += s[i];
        }
      }
      s = n;
      check = true;
    }
    cout << s << endl;
  }
  return 0;
}