#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FOD(i, a, b) for(int i = a; i >= b; i--)
#define int long long
#define fi first
#define se second
#define ll long long
#define db double
#define ii pair<int,int>
#define pb push_back
#define MASK(i) (1LL << i)
#define sq(i) (1LL * (i) * (i))
#define task "task"
const ll INF = 1e18;
const int inf = 1e9;
const int N = 5e5 + 4;
int n, q;
int a[N];
struct Node {
int L, R, S, A;
Node(int _a = 0, int _b = 0, int _s = 0, int _k = 0) {
L = _a;
R = _b;
S = _s;
A = _k;
}
};
Node emp = {-inf, -inf, 0};
struct Smt {
Node st[4 * N];
Node combine(Node a, Node b) {
Node ret;
ret.S = a.S + b.S;
ret.L = max(a.L, a.S + b.L);
ret.R = max(b.R, b.S + a.R);
ret.A = max({a.A + b.S, a.S + b.A, a.L + b.R});
return ret;
}
void build(int id, int l, int r) {
if(l == r) {
if(a[l] == 1) st[id] = {1, 1, 1, 1};
else st[id] = {0, 0, -1, 0};
return;
}
int mid = l + r >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = combine(st[id << 1], st[id << 1 | 1]);
}
Node get(int id, int l, int r, int u, int v) {
if(l > v || r < u) return emp;
if(l >= u && r <= v) return st[id];
int mid = l + r >> 1;
return combine(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
} smt;
signed main() {
if(fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
FOR(i, 1, n) {
char c;
cin >> c;
a[i] = (c == 'C' ? -1 : 1);
}
smt.build(1, 1, n);
cin >> q;
FOR(i, 1, q) {
int l, r;
cin >> l >> r;
cout << smt.get(1, 1, n, l, r).A << '\n';
}
}
Compilation message (stderr)
election.cpp: In function 'int main()':
election.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
69 | freopen(task".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
70 | freopen(task".out", "w", stdout);
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