Submission #1122478

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122478		KasymK	Bootfall (IZhO17_bootfall)	C++17	100 / 100	313 ms	2752 KiB

bootfall

#include "bits/stdc++.h"
using namespace std;
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define tr(i, c) for(auto i = c.begin(); i != c.end(); ++i)
#define wr puts("----------------")
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
const int N = 505;
int v[N], n, sm, cnt;
bitset<N*N> dp, vis, tmp;
 
struct node {
    int l, r;
    vector<int> val;
} seg[N<<2];
 
void bld(int x, int l, int r){
    seg[x].l = l, seg[x].r = r;
    if(l==r)
        return;
    int mid = (l+r)>>1;
    bld(x<<1, l, mid);
    bld(x<<1|1, mid+1, r);
}
 
void upd(int x, int l, int r, int u){
    if(l>r)
        return;
    if(l>seg[x].r or r<seg[x].l)
        return;
    if(l <= seg[x].l  and seg[x].r <= r){
        seg[x].val.pb(u);
        return;
    }
    upd(x<<1, l, r, u);
    upd(x<<1|1, l, r, u);
}
 
void qry(int x, bitset<N*N> wow){
    for(auto i : seg[x].val)
        wow=wow|(wow<<i);
    if(seg[x].l==seg[x].r){
        sm -= v[seg[x].l];
        vis.reset();
        for(int i = 0; i <= sm; ++i)
            if(wow[i]){
                int val = abs(sm-2*i);
                vis[val] = 1;
            }
        cnt++;
        if(cnt==1)
            tmp = vis;
        else
            tmp &= vis;
        sm += v[seg[x].l];
        return;
    }
    qry(x<<1, wow);
    qry(x<<1|1, wow);
}
 
int main(){
    // freopen("file.txt", "r", stdin);
    scanf("%d", &n);
    bld(1, 1, n);
    dp[0] = 1;
    for(int i = 1; i <= n; ++i){
        scanf("%d", v+i), sm += v[i];
        upd(1, 1, i-1, v[i]);
        upd(1, i+1, n, v[i]);
        dp=dp|(dp<<v[i]);
    }
    if(sm&1 or !dp[sm/2]){
        puts("0");
        return 0;
    }
    dp.reset();
    dp[0] = 1;
    qry(1, dp);
    vector<int> ans;
    for(int i = 0; i <= sm; ++i)
        if(tmp[i])
            ans.pb(i);
    printf("%d\n", (int)ans.size());
    for(auto i : ans)
        printf("%d ", i);
    puts("");
    return 0;
}

Compilation message (stderr)

bootfall.cpp: In function 'int main()':
bootfall.cpp:71:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
bootfall.cpp:75:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         scanf("%d", v+i), sm += v[i];
      |         ~~~~~^~~~~~~~~~~

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