Problem p01096 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
// #define LOG(...)
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())
#define RSORT(c) sort((c).rbegin(), (c).rend())
#define CLR(a) memset((a), 0, sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};

struct UnionFind {
  vector<int> v;
  UnionFind(int n) : v(n) {
    for (int i = 0; i < n; i++)
      v[i] = i;
  }
  int find(int x) { return v[x] == x ? x : v[x] = find(v[x]); }
  void unite(int x, int y) { v[find(x)] = find(y); }
};

int main() {
  int n;
  while (cin >> n, n) {
    vi num(n);
    REP(i, n)
    cin >> num[i];
    vector<vector<bool>> able(n, vb(n, false));
    for (int i = 2; i < n + 1; i += 2) {
      for (int j = 0; j + i - 1 < n; j++) {
        if (i == 2) {
          if (abs(num[j] - num[j + i - 1]) <= 1)
            able[j][j + i - 1] = true;
        } else {
          if (abs(num[j] - num[j + i - 1]) <= 1 && able[j + 1][j + i - 2])
            able[j][j + i - 1] = true;
          REP(k, i / 2 - 1)
          if (able[j][j + k * 2 + 1] && able[j + k * 2 + 2][j + i - 1])
            able[j][j + i - 1] = true;
        }
      }
    }
    vvi DP(n, vi(n, 0));
    REP(i, n)
    REP(j, n)
    if (able[i][j])
      DP[i][j] = j - i + 1;
    for (int i = 3; i < n + 1; i++) {
      for (int j = 0; j + i - 1 < n; j++)
        REP(k, i - 1)
      DP[j][j + i - 1] =
          max(DP[j][j + i - 1], DP[j][j + k] + DP[j + k + 1][j + i - 1]);
    }
    cout << DP[0][n - 1] << endl;
  }
}

Error: -11

Fixed submission:

#include <algorithm>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
// #define LOG(...)
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())
#define RSORT(c) sort((c).rbegin(), (c).rend())
#define CLR(a) memset((a), 0, sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};

struct UnionFind {
  vector<int> v;
  UnionFind(int n) : v(n) {
    for (int i = 0; i < n; i++)
      v[i] = i;
  }
  int find(int x) { return v[x] == x ? x : v[x] = find(v[x]); }
  void unite(int x, int y) { v[find(x)] = find(y); }
};

int main() {
  int n;
  while (cin >> n, n) {
    vi num(n);
    REP(i, n)
    cin >> num[i];
    vector<vector<bool>> able(n, vb(n, false));
    for (int i = 2; i < n + 1; i += 2) {
      for (int j = 0; j + i - 1 < n; j++) {
        if (i == 2) {
          if (abs(num[j] - num[j + i - 1]) <= 1)
            able[j][j + i - 1] = true;
        } else {
          if (abs(num[j] - num[j + i - 1]) <= 1 && able[j + 1][j + i - 2])
            able[j][j + i - 1] = true;
          REP(k, i / 2 - 1)
          if (able[j][j + k * 2 + 1] && able[j + k * 2 + 2][j + i - 1])
            able[j][j + i - 1] = true;
        }
      }
    }
    vvi DP(n, vi(n, 0));
    REP(i, n)
    REP(j, n)
    if (able[i][j])
      DP[i][j] = j - i + 1;
    for (int i = 3; i < n + 1; i++) {
      for (int j = 0; j + i - 1 < n; j++)
        REP(k, i)
      DP[j][j + i - 1] =
          max(DP[j][j + i - 1], DP[j][j + k] + DP[j + k + 1][j + i - 1]);
    }
    cout << DP[0][n - 1] << endl;
  }
}