Problem p00451 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define REP(i, m, n) for (int i = m; i < (int)n; i++)
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define rrep(i, n) for (int i = 1; i <= n; i++)
#define drep(i, n) for (int i = n; i >= 0; i--)
#define rp(i, c) rep(i, (int)c.size())
#define fr(i, c)                                                               \\
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define mp make_pair
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(u) (u).rbegin(), (u).rend()
#define dbg(x) cerr << #x << " = " << (x) << endl
#define v_delete(a, b) (a).erase(remove((a).begin(), (a).end(), b), (a).end())
#define v_unique(a) (a).erase(unique((a).begin(), (a).end()), (a).end())
#define VV(T) vector<vector<T>>
#define init(a, b) memset((a), (b), sizeof((a)))
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
const int inf = 1 << 28;
const double INF = 1e10, EPS = 1e-9;

template <class T> int SIZE(T a) { return a.size(); }
template <class T> string IntToString(T num) {
  string res;
  stringstream ss;
  ss << num;
  return ss.str();
}
template <class T> T StringToInt(string str) {
  T res = 0;
  for (int i = 0; i < SIZE(str); i++)
    res = (res * 10 + str[i] - '0');
  return res;
}
template <class T> T gcd(T a, T b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
template <class T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

template <class T> void input(T &a, int n) {
  for (int i = 0; i < n; ++i)
    cin >> a[i];
}
template <class T> void input(T *a, int n) {
  for (int i = 0; i < n; ++i)
    cin >> a[i];
}

int dp[4001][4001];
int main(void) {
  char s[4001], t[4001];
  //  printf("%d\\n",4000*4000);
  while (scanf("%s", s) != EOF) {
    scanf("%s", t);
    //      dp[0][0]=s[0]==t[0];
    for (int i = 0; i < 4001; i++)
      dp[i][0] = dp[0][i] = 0;
    int sl = strlen(s), tl = strlen(t);
    int ans = 0;
    for (int i = 1; i <= sl; i++) {
      for (int j = 1; j <= tl; j++) {
        if (s[i - 1] == t[j - 1]) {
          dp[i][j] = dp[i - 1][j - 1] + 1;
          ans = max(ans, dp[i][j]);
        } else
          dp[i][j] = 0;
      }
    }
    printf("%d\\n", ans);
  }
  return 0;
}

Error: -11

Fixed submission:

#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define REP(i, m, n) for (int i = m; i < (int)n; i++)
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define rrep(i, n) for (int i = 1; i <= n; i++)
#define drep(i, n) for (int i = n; i >= 0; i--)
#define rp(i, c) rep(i, (int)c.size())
#define fr(i, c)                                                               \\
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define mp make_pair
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(u) (u).rbegin(), (u).rend()
#define dbg(x) cerr << #x << " = " << (x) << endl
#define v_delete(a, b) (a).erase(remove((a).begin(), (a).end(), b), (a).end())
#define v_unique(a) (a).erase(unique((a).begin(), (a).end()), (a).end())
#define VV(T) vector<vector<T>>
#define init(a, b) memset((a), (b), sizeof((a)))
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
const int inf = 1 << 28;
const double INF = 1e10, EPS = 1e-9;

template <class T> int SIZE(T a) { return a.size(); }
template <class T> string IntToString(T num) {
  string res;
  stringstream ss;
  ss << num;
  return ss.str();
}
template <class T> T StringToInt(string str) {
  T res = 0;
  for (int i = 0; i < SIZE(str); i++)
    res = (res * 10 + str[i] - '0');
  return res;
}
template <class T> T gcd(T a, T b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
template <class T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

template <class T> void input(T &a, int n) {
  for (int i = 0; i < n; ++i)
    cin >> a[i];
}
template <class T> void input(T *a, int n) {
  for (int i = 0; i < n; ++i)
    cin >> a[i];
}

int main() {
  string a, b;
  while (cin >> a >> b) {
    int dp[4002][4002] = {0};
    int as = a.size();
    a += 'a';
    int bs = b.size();
    b += 'b';
    int ans = 0;
    for (int i = 0; i < as; i++) {
      for (int j = 0; j < bs; j++) {
        if (a[i + 1] == b[j + 1]) {
          dp[i + 1][j + 1] = dp[i][j] + 1;
        } else {
          dp[i + 1][j + 1] = 0;
        } /*
         if(dp[i+1][j+1]){
                 cout << dp[i+1][j+1]<<endl;
                 cout << i << "," << j << endl;
         }*/
        ans = max(ans, dp[i + 1][j + 1]);
      }
    }
    cout << ans << endl;
  }
  return 0;
}