Submission #1095038

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095038		cpptowin	Bootfall (IZhO17_bootfall)	C++17	100 / 100	436 ms	31752 KiB

bootfall

#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define bitcount(x) __builtin_popcountll(x)
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
#define ss(x) (int)x.size()
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}
using namespace std;
const int nsqrt = 450;
const int mod = 1e9 + 7;
void add(int &x, int k)
{
    x += k;
    x %= mod;
    if(x < 0) x += mod;
}
void del(int &x, int k)
{
    x -= k;
    x %= mod;
    if(x < 0) x += mod;
}
const int nn = 250001;
int n,a[555];
bitset<nn> p[502],s[502];
main()
{
#define name "TASK"
    if (fopen(name ".inp", "r"))
    {
        freopen(name ".inp", "r", stdin);
        freopen(name ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n;
    fo(i,1,n) cin >> a[i];
    int tot = 0;
    bitset<nn> checker;
    checker[0] = 1;
    fo(i,1,n) 
    {
        checker |= checker << a[i];
        tot += a[i];
    }
    if(tot % 2 == 1 or checker[tot / 2] == 0) return cout << 0,0;
    p[0][0] = s[n + 1][0] = 1;
    fo(i,1,n)
    {
        p[i] = p[i - 1];
        p[i] |= p[i] << a[i];
    }
    fod(i,n,1)
    {
        s[i] = s[i + 1];
        s[i] |= s[i] << a[i];
    }
    bitset<nn> odd,even,cur;
    even.set();
    odd.set();
    even[0] = 0;
    fo(i,1,n)
    {
        if(i > n / 2)
        {
            cur = p[i - 1];
            fo(j,i + 1,n) cur |= cur << a[j];
        }
        else 
        {
            cur = s[i + 1];
            fod(j,i - 1,0) cur |= cur << a[j];
        }
        int tot1 = tot - a[i];
        if(tot1 % 2 == 0)
        {
            odd &= 0;
            even &= cur >> (tot1 / 2);
        }
        else 
        {
            even &= 0;
            odd &= cur >> ((tot1 + 1) / 2);
        }
    }
    cout << even.count() + odd.count();en;
    fo(i,1,tot / 2) if(even[i]) cout << i * 2 << ' ';
    fo(i,0,(tot + 1) / 2) if(odd[i]) cout << i * 2 + 1 << ' ';
}

Compilation message (stderr)

bootfall.cpp:58:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   58 | main()
      | ^~~~
bootfall.cpp: In function 'int main()':
bootfall.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen(name ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bootfall.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(name ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 21 / 21
• Subtask 6: 35 / 35