#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll INF = 1e9+7;
ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
struct node{
ll sum;
ll mpre;
ll msuf;
};
node seg[2000005];
string S;
void build(ll idx,ll s, ll e){
if(e == s){
ll v = 1;
if(S[e-1] == 'C'){
v = -1;
}
seg[idx].sum = v;
seg[idx].mpre = seg[idx].msuf = max(0LL,v);
return;
}
ll mid = (e+s)/2;
build(idx*2,s,mid);
build(idx*2+1,mid+1,e);
seg[idx].sum = seg[idx*2].sum + seg[idx*2+1].sum;
seg[idx].mpre = max(seg[idx*2].mpre,seg[idx*2].sum+seg[idx*2+1].mpre);
seg[idx].msuf = max(seg[idx*2+1].msuf,seg[idx*2+1].sum+seg[idx*2].msuf);
}
node query(ll idx,ll s,ll e,ll qs, ll qe){
node anss;
if(qs <= s && e <= qe){
return seg[idx];
}
if(qs > e || qe < s){
anss.sum = anss.mpre = anss.msuf = 0;
return anss;
}
ll mid = (e+s)/2;
node a = query(idx*2,s,mid,qs,qe);
node b = query(idx*2+1,mid+1,e,qs,qe);
anss.sum = a.sum + b.sum;
anss.mpre = max(a.mpre,a.sum+b.mpre);
anss.msuf = max(b.msuf,b.sum+a.msuf);
return anss;
}
int main(void){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n,q;
cin>>n;
string s;
cin>>s;
cin>>q;
ll team[n+1] = {0};
S = s;
build(1,1,n);
for(ll i = n-1;i >= 0;i--){
if(s[i] == 'T'){
if(query(1,1,n,i+2,n).mpre <= 0){
team[i+1] = i+1;
}
else{
ll l = i+2,r = n;
ll ans = n;
while(l <= r){
ll mid = (l+r)/2;
if(query(1,1,n,i+2,mid).mpre > 0){
r = mid - 1;
ans = min(ans,mid);
}
else{
l = mid + 1;
}
}
team[i+1] = ans;
}
}
}
while(q--){
ll L,R;
cin>>L>>R;
ll ans = 0;
ll POS = L,POS2 = -1;
if(query(1,1,n,L,R).mpre > 0){
ll l = L,r = R;
ll res = R;
while(l <= r){
ll mid = (l+r)/2;
if(query(1,1,n,L,mid).mpre > 0){
r = mid - 1;
res = min(res,mid);
}
else{
l = mid + 1;
}
}
ll T = res;
ans = 1;
while(team[T] <= R && T != team[T]){
ans++;
T = team[T];
}
/*
ll posl = lower_bound(all(arr[T]),res) - arr[T].begin();
ll P = upper_bound(all(arr[T]),R) - arr[T].begin();
ll posr = min((ll)arr[T].size() - 1,P);
ans += posr - posl + 1;
*/
POS = T + 1;
POS2 = res - 1;
}
ll ANS = 0;
ll cur = 0;
bool allaxa[n] = {0};
f(j,L-1,R){
if(s[j] == 'T'){
cur++;
}
else{
cur--;
}
if(cur == 1){
ANS++;
allaxa[j] = 1;
cur--;
}
}
assert(ans == ANS);
ans += query(1,1,n,POS,R).msuf;
cur = 0;
for(ll j = R-1;j >= POS-1;j--){
if(allaxa[j]){
continue;
}
if(s[j] == 'T'){
cur++;
}
else{
cur--;
}
if(cur == 1){
ANS++;
allaxa[j] = 1;
cur--;
}
}
assert(ANS == ans);
if(POS2 != -1){
ans += max(0LL,query(1,1,n,L,POS2).msuf + query(1,1,n,POS,R).sum - query(1,1,n,POS,R).msuf);
}
/*
cur = 0;
for(ll j = R-1;j >= L-1;j--){
if(allaxa[j]){
continue;
}
if(s[j] == 'T'){
cur++;
}
else{
cur--;
}
if(cur == 1){
ANS++;
cur--;
}
}
assert(ANS == ans);
*/
cout<<ans<<"\n";
}
}
/*
11
CCCTTTTTTCC
3
1 11
4 9
1 6
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
15 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
15 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
15 ms |
332 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
