Problem p02716 (C++) — buggy submission, verdict: Runtime Error

/*
これを入れて実行
g++ code.cpp
./a.out
 */

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <utility>
#include <vector>

#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef long double ld;

int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

const long long INF = 1LL << 62;
const ll MOD = 1e9 + 7;

bool greaterSecond(const pair<int, int> &f, const pair<int, int> &s) {
  return f.second > s.second;
}

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

ll conbinationMemo[100][100];

void cmemoInit() {
  rep(i, 100) {
    rep(j, 100) { conbinationMemo[i][j] = -1; }
  }
}

ll nCr(ll n, ll r) {
  if (conbinationMemo[n][r] != -1)
    return conbinationMemo[n][r];
  if (r == 0 || r == n) {
    return 1;
  } else if (r == 1) {
    return n;
  }
  return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}

ll nPr(ll n, ll r) {
  r = n - r;
  ll ret = 1;
  for (ll i = n; i >= r + 1; i--)
    ret *= i;
  return ret;
}
//-----------------------ここから-----------
ll n;
vector<ll> a;
ll memo[200100][5][5];
ll rec(ll i, ll j, ll k) {
  if (i <= 0 && j == 0 && k == 0)
    return 0;
  if (i <= 0)
    return -INF;
  if (memo[i][j][k] != -INF)
    return memo[i][j][k];

  ll res = -INF;
  if (k > 0)
    res = max(res, rec(i - 4, j, k - 1) + a[i - 4]);
  if (j > 0)
    res = max(res, rec(i - 3, j - 1, k) + a[i - 3]);
  res = max(res, rec(i - 2, j, k) + a[i - 2]);

  return memo[i][j][k] = res;
}
int main(void) {
  cin >> n;
  a.resize(n);
  rep(i, n) cin >> a[i];

  vector<ll> e, o;
  e.push_back(0);
  o.push_back(0);

  for (int i = 0; i < n; i += 2) {
    e.push_back(e.back() + a[i]);
  }
  for (int i = 1; i < n; i += 2) {
    o.push_back(o.back() + a[i]);
  }

  if (n % 2 == 0) {
    ll ans = -INF;
    ans = max(e.back(), o.back());
    for (int i = 0; i <= n / 2; i++) {
      ans = max(ans, o[n / 2] - o[i] + e[i]);
    }
    cout << ans << endl;
  } else {
    rep(i, 200100) {
      rep(j, 5) {
        rep(k, 5) { memo[i][j][k] = -INF; }
      }
    }

    cout << max(rec(n + 1, 2, 0), rec(n + 1, 0, 1)) << endl;
  }
}


Error: 0

Fixed submission:

/*
これを入れて実行
g++ code.cpp
./a.out
 */

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <stack>
#include <stdio.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <utility>
#include <vector>

#define all(x) (x).begin(), (x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef long double ld;

int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

const long long INF = 1LL << 62;
const ll MOD = 1e9 + 7;

bool greaterSecond(const pair<int, int> &f, const pair<int, int> &s) {
  return f.second > s.second;
}

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

ll conbinationMemo[100][100];

void cmemoInit() {
  rep(i, 100) {
    rep(j, 100) { conbinationMemo[i][j] = -1; }
  }
}

ll nCr(ll n, ll r) {
  if (conbinationMemo[n][r] != -1)
    return conbinationMemo[n][r];
  if (r == 0 || r == n) {
    return 1;
  } else if (r == 1) {
    return n;
  }
  return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}

ll nPr(ll n, ll r) {
  r = n - r;
  ll ret = 1;
  for (ll i = n; i >= r + 1; i--)
    ret *= i;
  return ret;
}
//-----------------------ここから-----------
ll n;
vector<ll> a;
ll memo[100100][5][5];
ll rec(ll i, ll j, ll k) {
  if (i <= 0 && j == 0 && k == 0)
    return 0;
  if (i <= 0)
    return -INF;
  if (memo[i][j][k] != -INF)
    return memo[i][j][k];

  ll res = -INF;
  if (k > 0)
    res = max(res, rec(i - 4, j, k - 1) + a[i - 4]);
  if (j > 0)
    res = max(res, rec(i - 3, j - 1, k) + a[i - 3]);
  res = max(res, rec(i - 2, j, k) + a[i - 2]);

  return memo[i][j][k] = res;
}
int main(void) {
  cin >> n;
  a.resize(n);
  rep(i, n) cin >> a[i];

  vector<ll> e, o;
  e.push_back(0);
  o.push_back(0);

  for (int i = 0; i < n; i += 2) {
    e.push_back(e.back() + a[i]);
  }
  for (int i = 1; i < n; i += 2) {
    o.push_back(o.back() + a[i]);
  }

  if (n % 2 == 0) {
    ll ans = -INF;
    ans = max(e.back(), o.back());
    for (int i = 0; i <= n / 2; i++) {
      ans = max(ans, o[n / 2] - o[i] + e[i]);
    }
    cout << ans << endl;
  } else {
    rep(i, 100100) {
      rep(j, 5) {
        rep(k, 5) { memo[i][j][k] = -INF; }
      }
    }

    cout << max(rec(n + 1, 2, 0), rec(n + 1, 0, 1)) << endl;
  }
}