Submission #891040

#	Time	Username	Problem	Language	Result	Execution time	Memory
891040		pcc	Alternating Heights (CCO22_day1problem1)	C++14	10 / 25	1033 ms	14160 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tlll tuple<ll,ll,ll>


const int mxn = 3030;
vector<int> paths[mxn];
int deg[mxn],arr[mxn];
int n,m;
int range[mxn];
queue<int> q;

bool check(int s,int e){
	bool flag = false;
	fill(deg+1,deg+m+1,0);
	for(int i = s+1;i<=e;i++){
		int a = arr[i-1],b = arr[i];
		if(flag)swap(a,b);
		flag ^= 1;
		deg[b]++;
		paths[a].push_back(b);
	}
	for(int i = 1;i<=m;i++)if(!deg[i])q.push(i);
	while(!q.empty()){
		auto now = q.front();
		q.pop();
		for(auto nxt:paths[now]){
			deg[nxt]--;
			if(!deg[nxt])q.push(nxt);
		}
	}
	for(int i = 1;i<=m;i++)paths[i].clear();
	if(*max_element(deg+1,deg+m+1) != 0)return false;
	else return true;
}

int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int q;
	cin>>n>>m>>q;
	for(int i = 1;i<=n;i++)cin>>arr[i];
	for(int i = 1;i<=n;i++){
		int l = i,r = n;
		while(l != r){
			int mid = (l+r+1)>>1;
			if(check(i,mid))l = mid;
			else r = mid-1;
		}
		range[i] = l;
	}
	while(q--){
		int l,r;
		cin>>l>>r;
		if(range[l]>=r)cout<<"YES\n";
		else cout<<"NO\n";
	}
	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 6 / 6
• Subtask 3: 0 / 7
• Subtask 4: 0 / 8