Submission #1095354

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095354		duyhoanho	Joker (BOI20_joker)	C++17	49 / 100	2058 ms	32708 KiB

Joker

#include<bits/stdc++.h>
#define int long long
#define forinc(i,a,b) for(int i=a;i<=b;i++)
#define fi first
#define se second
#define pii pair<int,int>
#define pb push_back
using namespace std;
const int N = 2e5+10, S = 448;
int n,m,q,p[N],sz[N],lz[N],x[N],y[N];
int ans[N];
bool ok;
stack<pii> sk,pr,si,la;
struct node
{
    int l,r,id;
} qu[N];
bool cmp(node a,node b)
{
    if(a.l / S != b.l / S) return a.l < b.l;
    return a.r > b.r;
}
int pa(int v,int &c)
{
    c ^= lz[v];
    if(p[v] == v) return v;
    return pa(p[v],c);
}
void join(int a,int b)
{
    int ca = 0;
    int cb = 0;
    a = pa(a,ca);
    b = pa(b,cb);
    if(sz[a] < sz[b]) swap(a,b);
    sk.push({a,b});
    si.push({sz[a],sz[b]});
    pr.push({p[a],p[b]});
    la.push({lz[a],lz[b]});
    if(a != b)
    {
        sz[a] += sz[b];
        p[b] = a;
        if(ca == cb) lz[b] = 1;
    }
}
void rollback()
{
    auto[a,b] = sk.top(); sk.pop();
    auto[sza,szb] = si.top();si.pop();
    sz[a] = sza;
    sz[b] = szb;
    auto[pa,pb] = pr.top(); pr.pop();
    p[a] = pa ;
    p[b] = pb;
    auto[lza,lzb] = la.top(); la.pop();
    lz[a] = lza ;
    lz[b] = lzb;
}
int get(int i)
{
    return (i - 1) / S + 1;
}
bool check(int a,int b)
{
    int ca = 0;
    int cb = 0;
    a = pa(a,ca);
    b = pa(b,cb);
    if(a == b && ca == cb) return true;
    return false;
}
int32_t main()
{
    if(fopen("task.inp","r"))
    {
        freopen("task.inp","r",stdin);
        freopen("task.out","w",stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m>>q;
    for(int i=1; i<=m; i++) cin>>x[i]>>y[i];
    forinc(i,1,q)
    {
        int l,r;
        cin>>l>>r;
        qu[i] = {l,r,i};
    }
    sort(qu+1,qu+q+1,cmp);
//    forinc(i,1,q) cout<<qu[i].l<<" "<<qu[i].r<<" "<<qu[i].id<<"\n";
    forinc(i,1,n)
    {
        sz[i] = 1;
        lz[i] = 0;
        p[i] = i;
    }
    for(int i=m; i>qu[1].r; i--)
    {
        if(check(x[i],y[i])) ok = 1;
          ans[qu[1].id] |= ok;
        join(x[i],y[i]);
    }
    for(int i=1; i<qu[1].l; i++)
    {
        if(check(x[i], y[i])) ans[qu[1].id] = 1;
        join(x[i],y[i]);
    }
    for(int t=2; t<=q; t++)
    {
//        auto[l,r,id] = qu[t];
        if(get(qu[t].l) == get(qu[t-1].l))
        {
            for(int i=1; i<qu[t-1].l; i++) rollback();
            ans[qu[t].id] |= ok;
            for(int i=qu[t-1].r ; i > qu[t].r ; i--)
            {
                if(check(x[i],y[i])) ok = 1;
                ans[qu[t].id] |= ok;
                //cout<<t<<" "<<i<<" "<<x[i]<<" "<<y[i]<<" "<<check(x[i],y[i])<<" "<<qu[t].id<<"\n";
                join(x[i],y[i]);
            }
            for(int i=1; i<qu[t].l; i++)
            {
                if(check(x[i],y[i])) ans[qu[t].id] = 1;
                join(x[i],y[i]);
            }
        }
        else
        {
            ok = 0;
            forinc(i,1,n)
            {
                sz[i] = 1;
                lz[i] = 0;
                p[i] = i;
            }
            while(sk.size())
            {
                sk.pop();
                la.pop();
                si.pop();
                pr.pop();
            }
            for(int i=m; i>qu[t].r; i--)
            {
                if(check(x[i],y[i])) ok = 1;
                ans[qu[t].id] |= ok;
                join(x[i],y[i]);
            }
            for(int i=1; i<qu[t].l; i++)
            {
                if(check(x[i], y[i])) ans[qu[t].id] = 1;
                join(x[i],y[i]);
            }
        }
    }
    forinc(i,1,q) cout<<(ans[i] == 1 ? "YES\n" : "NO\n");
}

Compilation message (stderr)

Joker.cpp: In function 'int32_t main()':
Joker.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen("task.inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen("task.out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 25 / 25
• Subtask 4: 10 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29