Submission #37481

#	Time	Username	Problem	Language	Result	Execution time	Memory
37481		Kerim	Bootfall (IZhO17_bootfall)	C++14	100 / 100	156 ms	3572 KiB

bootfall

#include "bits/stdc++.h"
#define MAXN 100009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
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;
bitset<N*N>dp;
int arr[N],vis[N];
bool ans[N*N];
vector<int>s[N*4];
int n,sum,total;
void upd(int l,int r,int v,int nd,int x,int y){
	if(l>y or x>r)
		return;
	if(l<=x and y<=r){
		s[nd].pb(v);
		return;
	}	
	int mid=(x+y)>>1;
	upd(l,r,v,nd<<1,x,mid);
	upd(l,r,v,nd<<1|1,mid+1,y);
}
void solve(int nd,int x,int y,bitset<N*N>tmp){
	tr(it,s[nd])
		tmp=tmp|(tmp<<(*it));
	if(x==y){
		if(vis[arr[x]])
			return;
		vis[arr[x]]=1;	
		total-=arr[x];
		for(int j=0;j<=sum;j++){
			if(!ans[j])
				continue;
			if((j+total)&1){
				ans[j]=0;
				continue;
			}	
			if(!tmp[(j+total)/2]){
				ans[j]=0;
				continue;
			}
		}
		total+=arr[x];
		return;	
	}
	int mid=(x+y)>>1;
	solve(nd<<1,x,mid,tmp);
	solve(nd<<1|1,mid+1,y,tmp);
}
int main(){
    //~ freopen("file.in", "r", stdin);
    scanf("%d",&n);
    dp[0]=1;
    for(int i=1;i<=n;i++){
		scanf("%d",arr+i);
		dp=dp|(dp<<arr[i]);
		upd(1,i-1,arr[i],1,1,n);
		upd(i+1,n,arr[i],1,1,n);
		sum+=arr[i];
	}
	if(sum&1 or !dp[sum/2]){
		puts("0");
		return 0;
	}	
	for(int j=0;j<=sum;j++)
		ans[j]=1;	
	total=sum;	
	dp.reset();dp[0]=1;
	solve(1,1,n,dp);	
	int res=0;
	for(int j=0;j<=sum;j++)
		res+=ans[j];
	printf("%d\n",res);	
	for(int j=0;j<=sum;j++)
		if(ans[j])
			printf("%d ",j);
	puts("");	
	return 0;
}

Compilation message (stderr)

bootfall.cpp: In function 'int main()':
bootfall.cpp:66:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
bootfall.cpp:69:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",arr+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