Submission #227267

#	Time	Username	Problem	Language	Result	Execution time	Memory
227267		stefanbalaz2	Port Facility (JOI17_port_facility)	C++14	0 / 100	4 ms	384 KiB

port_facility

/*



*/
#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
///#define ll long long
typedef pair<int,int> pii;
const int maxn=1e6+10;
int mod=1e9+7,e;
int n,kolko,rez,grane,sz[maxn],cc,levi[maxn];
pii niz[2*maxn],p[maxn];
void reset(){

    for(int i=1;i<=n;i++){
        p[i]={i,0};
        sz[i]=1;
    }
    cc=n;
}
pii root(int x){
    if(p[x].ff==x)return p[x];
    else{
        pii pom=root(p[x].ff);
        p[x]={pom.ff,p[x].ss^pom.ss};
        return p[x];
    }
}
int join(int x,int y){

    pii rx=root(x);
    pii ry=root(y);

    if(rx.ff==ry.ff){
        if(rx.ss=ry.ss)return 1;
        else return 0;
    }

    if(sz[rx.ff]<sz[ry.ff])swap(rx,ry),swap(x,y);

    cc--;
    p[ry.ff]={rx.ff,(rx.ss^ry.ss^1)};
    sz[rx.ff]+=sz[ry.ff];

    return 0;
}
int main(){

    ///freopen("test.txt","r",stdin);

    clock_t start=clock();

    scanf("%d",&n);
    reset();
    for(int i=1;i<=n;i++){
        int a,b;
        scanf("%d %d",&a,&b);
        niz[a]={i,1};
        niz[b]={i,-1};
        levi[i]=a;
    }

    set<pii>st;
    for(int i=1;i<=2*n;i++){

        if(niz[i].ss>0)st.insert({i,niz[i].ff});
        else{

            int id=niz[i].ff;
            int lb=levi[id];
            set<pii>::iterator it=st.find({levi[id],id});
            it++;

            ///printf("%d AAAAA\n",id);

            for(;it!=st.end();it++){
                int id2=(*it).ff;

                ///printf("%d AFSAFSAFSAFAS\n",id2);
                if(join(id,id2)){
                    printf("0\n");
                    return 0;
                }
            }

            st.erase(st.find({lb,id}));

            /*
            clock_t sad=clock();
            if((double)(sad-start)/CLOCKS_PER_SEC>5){
                printf("0\n");
                return 0;
            }*/
        }

    }

    rez=1;
    for(int i=1;i<=cc;i++){
        rez+=rez;
        if(rez>=mod)rez-=mod;
    }

    printf("%d\n",rez);

	return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'int join(int, int)':
port_facility.cpp:39:17: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
         if(rx.ss=ry.ss)return 1;
                 ^
port_facility.cpp: In function 'int main()':
port_facility.cpp:55:13: warning: unused variable 'start' [-Wunused-variable]
     clock_t start=clock();
             ^~~~~
port_facility.cpp:57:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
port_facility.cpp:61:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22