Problem p03161 (C++)

Buggy submission (status: Runtime Error):
// --------------------<optimizations>--------------------
#pragma GCC optimize("O3")
//(UNCOMMENT WHEN HAVING LOTS OF RECURSIONS)\
#pragma comment(linker, "/stack:200000000")
//(UNCOMMENT WHEN TRYING TO BRUTEFORCE WITH A LOT OF LOOPS)\
#pragma GCC optimize("unroll-loops")

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair<ll, ll>
#define vpii vector<pair<ll, ll>>
#define F first
#define S second
#define ld long double
#define built __builtin_popcountll
#define mst(a, i) memset(a, i, sizeof(a))
#define all(x) x.begin(), x.end()
#define itit(it, a) for (auto it = (a).begin(); it != (a).end(); it++)
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define repr(i, a, b) for (ll i = a; i > b; i--)
#define reprr(i, a, b) for (ll i = a; i >= b; i--)
#define pi 3.14159265358979323846264338327950288419716939937510582097494459230
ll max3(ll x, ll y, ll z) { return max(max(x, y), z); }
ll min3(ll x, ll y, ll z) { return min(min(x, y), z); }
const ll N = 1e5 + 10, M = 2e5 + 10, M2 = 1e6 + 10, mod = 1e9 + 7,
         inf = 1e17 + 10;
const int INF = 1e9 + 7;
void add(int &a, int b) {
  a += b;
  if (a >= mod) {
    a -= mod;
  }
}

#define trace(...)                                                             \
  cerr << "Line:" << __LINE__ << " ";                                          \
  __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}

int X[] = {0, 1, 0, -1};
int Y[] = {-1, 0, 1, 0};
// assic value of ('0'-'9') is(48 - 57) and (a-z) is (97-122) and (A-Z)
// is(65-90) and 32 for space
ll power(ll x, ll n) {
  ll result = 1;
  while (n > 0) {
    if (n % 2 == 1)
      result = (result * x) % mod;
    x = ((x % mod) * (x % mod)) % mod;
    n = n / 2;
  }
  return result;
}

int n, k;
int h[N];
int cache[N];

int dp(int idx) {
  if (idx >= n)
    return 0;
  int &ans = cache[idx];
  if (ans != -1)
    return ans;
  ans = inf;
  for (int i = 1; i <= k; i++) {
    ans = min(ans, dp(idx + i) + abs(h[idx + i] - h[idx]));
  }
  return ans;
}

int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k;
  rep(i, 1, n + 1) cin >> h[i];
  mst(cache, -1);
  int res = dp(1);
  cout << res;
  return 0;
}


Fixed submission:
// --------------------<optimizations>--------------------
#pragma GCC optimize("O3")
//(UNCOMMENT WHEN HAVING LOTS OF RECURSIONS)\
#pragma comment(linker, "/stack:200000000")
//(UNCOMMENT WHEN TRYING TO BRUTEFORCE WITH A LOT OF LOOPS)\
#pragma GCC optimize("unroll-loops")

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair<ll, ll>
#define vpii vector<pair<ll, ll>>
#define F first
#define S second
#define ld long double
#define built __builtin_popcountll
#define mst(a, i) memset(a, i, sizeof(a))
#define all(x) x.begin(), x.end()
#define itit(it, a) for (auto it = (a).begin(); it != (a).end(); it++)
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define repr(i, a, b) for (ll i = a; i > b; i--)
#define reprr(i, a, b) for (ll i = a; i >= b; i--)
#define pi 3.14159265358979323846264338327950288419716939937510582097494459230
ll max3(ll x, ll y, ll z) { return max(max(x, y), z); }
ll min3(ll x, ll y, ll z) { return min(min(x, y), z); }
const ll N = 1e5 + 10, M = 2e5 + 10, M2 = 1e6 + 10, mod = 1e9 + 7,
         inf = 1e17 + 10;
const int INF = 1e9 + 7;
void add(int &a, int b) {
  a += b;
  if (a >= mod) {
    a -= mod;
  }
}

#define trace(...)                                                             \
  cerr << "Line:" << __LINE__ << " ";                                          \
  __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}

int X[] = {0, 1, 0, -1};
int Y[] = {-1, 0, 1, 0};
// assic value of ('0'-'9') is(48 - 57) and (a-z) is (97-122) and (A-Z)
// is(65-90) and 32 for space
ll power(ll x, ll n) {
  ll result = 1;
  while (n > 0) {
    if (n % 2 == 1)
      result = (result * x) % mod;
    x = ((x % mod) * (x % mod)) % mod;
    n = n / 2;
  }
  return result;
}

int n, k;
int h[N];
int cache[N];

int dp(int idx) {
  if (idx >= n)
    return 0;
  int &ans = cache[idx];
  if (ans != -1)
    return ans;
  ans = inf;
  for (int i = 1; i <= k; i++) {
    if (i + idx <= n)
      ans = min(ans, dp(idx + i) + abs(h[idx + i] - h[idx]));
  }
  return ans;
}

int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k;
  rep(i, 1, n + 1) cin >> h[i];
  mst(cache, -1);
  int res = dp(1);
  cout << res;
  return 0;
}