답안 #73863 :: oj.uz

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
73863	2018-08-29T07:19:24 Z	zscoder	Election (BOI18_election)	C++17	82 / 100	3000 ms	263168 KB

election

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
#define fi first
#define se second
#define mp make_pair
#define pb push_back
 
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef long double ld; 
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> pbds;

string s;
int n;
int del[555555];

int solve_naive(int l, int r)
{
	int cnt=0;
	for(int i=l;i<=r;i++) del[i]=0;
	int ans=0; int S=0; int minpref=0;
	for(int i=l;i<=r;i++)
	{
		S+=(s[i]=='C'?1:-1);
		if(s[i]=='C') cnt++;
		else cnt--;
		if(cnt<0)
		{
			del[i]=1; ans++;
			cnt++;
		}
	}
	minpref=-ans;
	int positive = S - minpref;
	cnt=0; int mx=0;
	for(int i=r;i>=l;i--)
	{
		if(del[i]) 
		{
			cnt = positive; continue;
		}
		if(s[i]=='C') cnt++;
		else cnt--;
		if(cnt<0)
		{
			mx=max(mx,abs(cnt));	
		}
	}
	return ans+mx;
}


struct node
{
	int sum;
	vi vec;
	vi sufmax;
	int minprefback;
	vi prefmax;
	int lastneg;
};

node st[511111*4];

void outnode(node S)
{
	cout<<"SUM : "<<S.sum<<'\n';
	for(int v:S.vec)
	{
		cout<<v<<' ';
	}
	cout<<'\n';
	cout<<"MIN PREF FROM BACK : "<<S.minprefback<<'\n';
	cout<<"LAST NEGATIVE : "<<S.lastneg<<'\n';
}

node compute(int l, int r)
{
	node N;
	N.sum=0;
	for(int i=l;i<=r;i++) del[i]=0;
	int cnt=0; int minpref=0;
	for(int i=l;i<=r;i++)
	{
		N.sum+=(s[i]=='C'?1:-1);
		cnt+=(s[i]=='C'?1:-1);
		if(cnt<0)
		{
			del[i]=1; cnt++; minpref--;
		}
	}
	N.minprefback=0; cnt=0;
	for(int i=r;i>=l;i--)
	{
		cnt+=(s[i]=='C'?1:-1);
		N.minprefback=min(N.minprefback, cnt);
	}
	N.minprefback*=-1;
	cnt=0; int mn = 0; bool ex=0; N.lastneg=0;
	for(int i=r;i>=l;i--)
	{
		if(del[i])
		{
			if(!ex)
			{
				N.lastneg=abs(mn);
			}
			else
			{
				N.vec.pb(abs(mn));
			}
			cnt=0; mn=0;
			ex=1;
		}
		else
		{
			cnt+=(s[i]=='C'?1:-1);
			mn = min(mn, cnt);
		}
	}
	if(!ex)
	{
		N.lastneg = abs(mn);
	}
	else
	{
		N.vec.pb(abs(mn));
	}
	reverse(N.vec.begin(),N.vec.end());
	N.sufmax.resize(int(N.vec.size()));
	for(int i=int(N.vec.size())-1;i>=0;i--)
	{
		N.sufmax[i] = N.vec[i];
		if(i+1<N.vec.size()) N.sufmax[i]=max(N.sufmax[i+1], N.sufmax[i]);
	}
	N.prefmax.resize(int(N.vec.size()));
	for(int i=0;i<N.vec.size();i++)
	{
		N.prefmax[i] = N.vec[i]-i;
		if(i>0) N.prefmax[i]=max(N.prefmax[i-1],N.prefmax[i]);
	}
	return N;
}

void build(int id, int l, int r)
{
	st[id] = compute(l,r-1);
	if(r-l<2) return ;
	int mid=(l+r)>>1;
	build(id*2,l,mid); build(id*2+1,mid,r);
}

vi query(int id, int l, int r, int ql, int qr) //get which nodes i need to care for my query
{
	if(ql>=r||l>=qr) return {};
	if(ql<=l&&r<=qr) 
	{
		//cerr<<"NODE : "<<l<<' '<<r-1<<'\n';
		return {id};
	}
	int mid=(l+r)>>1;
	vi L=query(id*2,l,mid,ql,qr);
	vi R=query(id*2+1,mid,r,ql,qr);
	for(int x:R) L.pb(x);
	return L;
}
const int DEBUG = 0;
int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	if(!DEBUG)
	{
		cin>>n; cin>>s;
	}
	if(DEBUG)
	{
		srand(time(NULL));
		freopen("election_boi.in","w",stdout);
		n=100; 
		for(int i=0;i<n;i++) s+=(rand()&1?'C':'T');
	}
	if(DEBUG) cout<<n<<'\n'<<s<<'\n';
	int q; 
	if(!DEBUG) cin>>q;
	if(DEBUG) 
	{
		q=500;
		cout<<q<<'\n';
	}
	build(1,0,n);
	//outnode(st[1]);
	for(int i=0;i<q;i++)
	{
		int l,r; 
		if(!DEBUG)
		{
			cin>>l>>r; l--; r--;
		}
		if(DEBUG)
		{
			l=rand()%n; r=rand()%n;
			if(l>r) swap(l,r);
			cout<<l+1<<' '<<r+1<<'\n';
		}
		vector<int> nodes = query(1,0,n,l,r+1);
		int Lcnt = 0; 
		int Rcnt = 0;
		int maxmiddle = 0;
		int curL = 0; int minpref = 0;
		for(int v:nodes)
		{
			//curL of the vec elements will be rekted
			int badbrackets = st[v].vec.size();
			if(badbrackets==0)
			{
				minpref = max(st[v].lastneg, minpref - st[v].sum);
				curL += st[v].sum;
			}
			else
			{
				if(curL>=badbrackets)
				{
					minpref = max(st[v].minprefback, minpref - st[v].sum);
					curL-=badbrackets;
					curL+=st[v].sum+badbrackets;
				}
				else
				{
					maxmiddle = max(maxmiddle, st[v].prefmax[curL] + curL);
					maxmiddle = max(maxmiddle, minpref + curL);
					Lcnt += badbrackets - curL;
					if(curL+1<st[v].sufmax.size()) maxmiddle = max(maxmiddle, st[v].sufmax[curL+1]);
					curL = st[v].sum + badbrackets;
					minpref = st[v].lastneg;
				}
			}
			/*
			outnode(st[v]);
			cerr<<"MINPREF : "<<minpref<<'\n';
			cerr<<"CURL : "<<curL<<'\n';
			cerr<<"LCNT : "<<Lcnt<<'\n';
			cerr<<'\n';
			*/
		}
		Rcnt = max(Rcnt, max(minpref, maxmiddle - curL));
		int ans=Lcnt+Rcnt;
		if(DEBUG)
		{
			if(ans!=solve_naive(l,r))
			{
				assert(0);
				cerr<<"HERE"<<'\n';
			}
			cerr<<ans<<' '<<solve_naive(l,r)<<'\n';
		}
		else
		{
			//cout<<ans<<' '<<solve_naive(l,r)<<'\n';
			cout<<ans<<'\n';
		}
		//cout<<solve(l,r)<<'\n';
	}
}

Compilation message

election.cpp: In function 'node compute(int, int)':
election.cpp:140:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(i+1<N.vec.size()) N.sufmax[i]=max(N.sufmax[i+1], N.sufmax[i]);
      ~~~^~~~~~~~~~~~~
election.cpp:143:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<N.vec.size();i++)
              ~^~~~~~~~~~~~~
election.cpp: In function 'int main()':
election.cpp:238:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      if(curL+1<st[v].sufmax.size()) maxmiddle = max(maxmiddle, st[v].sufmax[curL+1]);
         ~~~~~~^~~~~~~~~~~~~~~~~~~~
election.cpp:184:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen("election_boi.in","w",stdout);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
28.0 / 28.0

#	결과	실행 시간	메모리	Grader output
1	Correct	184 ms	192632 KB	Output is correct
2	Correct	167 ms	192744 KB	Output is correct
3	Correct	183 ms	192744 KB	Output is correct
4	Correct	175 ms	192848 KB	Output is correct
5	Correct	186 ms	192848 KB	Output is correct

Subtask #2
54.0 / 54.0

#	결과	실행 시간	메모리	Grader output
1	Correct	184 ms	192632 KB	Output is correct
2	Correct	167 ms	192744 KB	Output is correct
3	Correct	183 ms	192744 KB	Output is correct
4	Correct	175 ms	192848 KB	Output is correct
5	Correct	186 ms	192848 KB	Output is correct
6	Correct	606 ms	201532 KB	Output is correct
7	Correct	647 ms	202404 KB	Output is correct
8	Correct	562 ms	203264 KB	Output is correct
9	Correct	489 ms	204248 KB	Output is correct
10	Correct	615 ms	204248 KB	Output is correct
11	Correct	542 ms	209540 KB	Output is correct
12	Correct	524 ms	211116 KB	Output is correct
13	Correct	565 ms	216384 KB	Output is correct
14	Correct	492 ms	216384 KB	Output is correct
15	Correct	556 ms	216384 KB	Output is correct

Subtask #3
0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	184 ms	192632 KB	Output is correct
2	Correct	167 ms	192744 KB	Output is correct
3	Correct	183 ms	192744 KB	Output is correct
4	Correct	175 ms	192848 KB	Output is correct
5	Correct	186 ms	192848 KB	Output is correct
6	Correct	606 ms	201532 KB	Output is correct
7	Correct	647 ms	202404 KB	Output is correct
8	Correct	562 ms	203264 KB	Output is correct
9	Correct	489 ms	204248 KB	Output is correct
10	Correct	615 ms	204248 KB	Output is correct
11	Correct	542 ms	209540 KB	Output is correct
12	Correct	524 ms	211116 KB	Output is correct
13	Correct	565 ms	216384 KB	Output is correct
14	Correct	492 ms	216384 KB	Output is correct
15	Correct	556 ms	216384 KB	Output is correct
16	Execution timed out	3051 ms	263168 KB	Time limit exceeded
17	Halted	0 ms	0 KB	-

답안 #73863

Compilation message

Subtask #1 28.0 / 28.0

Subtask #2 54.0 / 54.0

Subtask #3 0 / 18.0

Subtask #1
28.0 / 28.0

Subtask #2
54.0 / 54.0

Subtask #3
0 / 18.0