#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 3;
int n, q;
string s;
struct Segment_Tree{
struct Node{
int prefix, suffix, sum;
Node(){}
Node(int x): prefix(max(x, 0)), suffix(max(x, 0)), sum(x){}
friend Node merge(Node l, Node r){
Node ret;
ret.sum = l.sum + r.sum;
ret.prefix = max(l.prefix, r.prefix + l.sum);
ret.suffix = max(r.suffix, l.suffix + r.sum);
return ret;
}
};
Node nd[4 * N];
void init(int i = 0, int l = 0, int r = n - 1){
if(l == r){
nd[i] = Node((s[l] == 'C') ? -1 : 1);
return;
}
int mid = (l + r) >> 1;
init(2 * i + 1, l, mid);
init(2 * i + 2, mid + 1, r);
nd[i] = merge(nd[2 * i + 1], nd[2 * i + 2]);
}
Node query(int l2, int r2, int i = 0, int l = 0, int r = n - 1){
if(l2 <= l && r <= r2) return nd[i];
int mid = (l + r) >> 1;
if(mid >= l2){
if(mid + 1 <= r2)
return merge(query(l2, r2, 2 * i + 1, l, mid), query(l2, r2, 2 * i + 2, mid + 1, r));
return query(l2, r2, 2 * i + 1, l, mid);
}
return query(l2, r2, 2 * i + 2, mid + 1, r);
}
} st;
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> s;
st.init();
cin >> q;
for(int i = 0; i < q; ++i){
int l, r;
cin >> l >> r;
--l, --r;
Segment_Tree::Node ans = st.query(l, r);
cout << max(ans.prefix, ans.suffix) << "\n";
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |