Submission #1241344

#	Time	Username	Problem	Language	Result	Execution time	Memory
1241344		sitingfake	Bootfall (IZhO17_bootfall)	C++20	100 / 100	424 ms	31672 KiB

bootfall

#include<bits/stdc++.h>
using namespace std;

// define

#define execute cerr << " Time: " << fixed << setprecision(6) << (1.0 * clock() / CLOCKS_PER_SEC) << "s\n";
#define ll long long
#define ld double
#define ii pair<int,int>
#define se second
#define fi first
#define iii pair<int,ii>
#define all(v) v.begin(),v.end()
#define bit(x,i) (((x)>>(i))&1LL)
#define flip(x,i) ((x)^(1LL<<(i)))
#define ms(d,x) memset(d,x,sizeof(d))
#define sitingfake 1
#define orz 1
#define exist __exist
#define ends __ends
#define visit visited
#define left __left
#define right __right

//constant

const ll mod = 1e9 + 7;
const long long linf = 4557430888798830399;
const int inf = 1061109567;
const int maxarr = 1e6 + 5;
int dx[] = {0 , -1 , 0 , 1};
int dy[] = {-1 , 0 , 1 , 0};

template<typename T> bool maximize(T &a, const T &b)
{
    if(a < b) {a = b; return 1;}
    return 0;
}

template<typename T> bool minimize(T &a, const T &b)
{
    if(a > b) {a = b; return 1;}
    return 0;
}

inline void Plus(ll & a ,ll b)
{
    b %= mod;
    a += b;
    if(a >= mod) a -= mod;
    if(a < 0) a += mod;
    return;
}

inline void Mul(ll & a, ll b)
{
    a %= mod; b %= mod;
    a *= b;
    a %= mod;
    return;
}

//code

const int maxn = 505;

int a[maxn];

int n;
int sum = 0;

bitset <250001> dp , ans , pre[maxn] , suf[maxn];

void solve(void)
{
    cin >> n;

    for(int i = 1; i <= n; i++)
    {
        cin >> a[i];
        sum += a[i];
    }

    if(sum & 1)
    {
        cout << 0;
        return;
    }

    dp[0] = 1;

    for(int i = 1; i <= n; i++)
    {
        dp |= (dp << a[i]);
    }

    if(!dp[sum / 2])
    {
        cout << 0;
        return;
    }

    pre[0][sum] = 1;

    for(int i = 1; i <= n; i++)
    {
        pre[i] = pre[i - 1] | (pre[i - 1] >> (2 * a[i]));
    }

    suf[n + 1][sum] = 1;

    for(int i = n; i >= 1; i--)
    {
        suf[i] = suf[i + 1] | (suf[i + 1] >> (2 * a[i]));
    }

    dp.reset();
    ans.set();

    for(int i = 1; i <= n; i++)
    {
        if(i > n / 2)
        {
            dp = pre[i - 1];

            for(int j = i + 1; j <= n; j++)
            {
                dp |= (dp >> (2 * a[j]));
            }
        }
        else
        {
            dp = suf[i + 1];

            for(int j = i - 1; j >= 1; j--)
            {
                dp |= (dp >> (2 * a[j]));
            }
        }

        dp >>= a[i];

        ans &= dp;

        dp.reset();
    }

    cout << ans.count() << "\n";

    for(int i = 1; i <= 250000; i++)
    {
        if(ans[i])
        {
            cout << i << " ";
        }
    }

}
/**
4
1 315
**/
signed main()
{
   ios_base::sync_with_stdio(0);
   cin.tie(0);
   cout.tie(0);

   #define task ""

   if(fopen(task".inp","r"))
   {
       freopen(task".inp","r",stdin);
       freopen(task".out","w",stdout);
   }

   int tc; tc = 1;

   while(tc--) solve();

   //execute;
}

Compilation message (stderr)

bootfall.cpp: In function 'int main()':
bootfall.cpp:173:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  173 |        freopen(task".inp","r",stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
bootfall.cpp:174:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  174 |        freopen(task".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