Submission #1054523

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054523		allin27x	Joker (BOI20_joker)	C++17	49 / 100	2055 ms	12856 KiB

Joker

#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9+7;
#define forn(i,n) for(int i=0; i<n; i++)
#define readv(a,n) vector<int>a(n);forn(i,n)cin>>a[i];
#define readvv(a,n,m) vector<vector<int>> a(n,vector<int>(m));forn(i,n)forn(j,m)cin>>a[i][j];
#define all(a) a.begin(), a.end()
#define _max(x,y) x = max(x,y)
#define _min(x,y) x = min(x,y)
// #define f first
// #define s second

const int N = 2e5+4;
const int SQRT = 460;
int ans[N];

struct qr{
	int l, r, i;
	bool operator<(qr b){
		return make_pair(l/SQRT, r) < make_pair(b.l/SQRT,b.r);
	}
};

vector<qr> queries[SQRT];
int edges[N][2];

int e1[2*N];
void build1(int N) {for (int i=0; i<N; i++) e1[i] = -1;}
int get1(int x) { return e1[x] < 0 ? x : e1[x] = get1(e1[x]); }
bool conn1(int a, int b) { return get1(a) == get1(b); }
int size1(int x) { return -e1[get1(x)]; }
void unite1(int x, int y) {
	x = get1(x), y = get1(y);
	if (x == y) return;
	if (e1[x] > e1[y]) swap(x, y);
	e1[x] += e1[y];
	e1[y] = x;
}
int nd = 0;
int ch[2*N];

int e2[2*N];
void build2(int N) {for (int i=0; i<N; i++) e2[i] = -1;}
int get2(int x) { 
	if (e2[x] < 0) return x;
	ch[nd++] = x;
	return e2[x] = get2(e2[x]); 

}
bool conn2(int a, int b) { return get2(a) == get2(b); }
int size2(int x) { return -e2[get2(x)]; }
void unite2(int x, int y) {
	x = get2(x), y = get2(y);
	if (x == y) return;
	if (e2[x] > e2[y]) swap(x, y);
	ch[nd++] = x; ch[nd++] = y;
	e2[x] += e2[y];
	e2[y] = x;
}

int st[2*N];

void solve(){
	int n,m,q; cin>>n>>m>>q;
	for (int i=0; i<m; i++){
		int a,b; cin>>a>>b; a--;b--; edges[i][0]=a; edges[i][1] = b;
	}
	for (int i=0; i<q; i++){
		int l,r; cin>>l>>r; l--; r--;
		qr p; p.l=l;p.r=r;p.i=i;
		queries[l/SQRT].push_back(p);
	}
	for (int i=0; i<SQRT; i++) sort(queries[i].begin(), queries[i].end());
	build1(2*n); build2(2*n);
	int fM =0; 
	for (int t=0; t<SQRT; t++){
		for (int i=0; i<2*n; i++) e2[i] = e1[i],st[i] = e2[i];
		if (t*SQRT >= m) break;
		int fm = 0;
		int i = m-1; int j = queries[t].size()-1;
		while (i>=0){
			if (j<0) break;
			qr p = queries[t][j];
			while (p.r == i){
				int f = 0;
				nd = 0;
				for (int ll=t*SQRT; ll<p.l; ll++){
					if (conn2(edges[ll][0],edges[ll][1])) f++;
					unite2(edges[ll][0]+n, edges[ll][1]);
					unite2(edges[ll][0], edges[ll][1]+n);
				}
				for (int rr =0; rr<nd; rr++){
					e2[ch[rr]] = st[ch[rr]];
				}
				if (f || fm || fM) ans[p.i] = 1;
				j--;
				if (j<0) break;
				p = queries[t][j];
			}
			if (j<0) break;
			nd = 0;
			fm += conn2(edges[i][0], edges[i][1]);
			unite2(edges[i][0] + n, edges[i][1]);
			unite2(edges[i][0], edges[i][1] + n);
			for (int rr =0; rr<nd; rr++){
				st[ch[rr]] = e2[ch[rr]];
			}
			i--;
		}
		for (int ll=SQRT*t; ll<min(m, SQRT*t + SQRT); ll++){
			fM += conn1(edges[ll][0], edges[ll][1]);
			unite1(edges[ll][0] + n, edges[ll][1]);
			unite1(edges[ll][0], edges[ll][1] + n);
		}
	}
	for (int i=0;i<q; i++) cout<<(ans[i]?"YES\n":"NO\n");
}


signed main(){ 
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int t=1;
	while(t--){
		solve();
	}	
	return 0;
}

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