#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(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) 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;
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n; cin>>s;
int q; cin>>q;
build(1,0,n);
//outnode(st[1]);
for(int i=0;i<q;i++)
{
int l,r; cin>>l>>r; l--; r--;
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;
}
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;
}
}
}
Rcnt = max(Rcnt, max(minpref, maxmiddle - curL));
cout<<Lcnt+Rcnt<<'\n';
//cout<<solve(l,r)<<'\n';
}
}
Compilation message
election.cpp: In function 'node compute(int, int)':
election.cpp:141:9: 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:144:15: 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:207:15: 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]);
~~~~~~^~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
199 ms |
192632 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
199 ms |
192632 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
199 ms |
192632 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
