Problem p03087 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <bitset>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
typedef long double ld;
const ll INF = 1e+14;
typedef pair<int, int> P;
#define stop                                                                   \
  char nyaa;                                                                   \
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ld, ld> LDP;
typedef pair<ll, ll> LP;
#define fr first
#define sc second
#define all(c) c.begin(), c.end()
#define pb push_back

void Yes() {
  cout << "Yes" << endl;
  exit(0);
}

void No() {
  cout << "No" << endl;
  exit(0);
}
int main() {
  ll N;
  cin >> N;
  ll Q;
  cin >> Q;
  string S;
  cin >> S;
  ll L[Q];
  ll R[Q];
  rep(i, Q) {
    ll a, b;
    cin >> a >> b;
    L[i] = a;
    R[i] = b;
  }

  vector<ll> A;
  rep(i, N - 1) {
    if (S[i] == 'A' && S[i + 1] == 'C')
      A.push_back(i);
    else
      continue;
  }

  ll count = 0;
  ll count1 = 0;
  ll B[N];
  rep(i, N) { B[i] = 0; }
  rep(i, N) {
    B[i] = count;
    if (A[count1] == i) {
      count++;
      count1++;
    }
  }

  rep(i, Q) {
    ll a = L[i] - 1;
    ll b = R[i] - 1;
    ll ans = B[b] - B[a];
    cout << ans << endl;
  }
}


Fixed submission:
#include <algorithm>
#include <bitset>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
typedef long double ld;
const ll INF = 1e+14;
typedef pair<int, int> P;
#define stop                                                                   \
  char nyaa;                                                                   \
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ld, ld> LDP;
typedef pair<ll, ll> LP;
#define fr first
#define sc second
#define all(c) c.begin(), c.end()
#define pb push_back

void Yes() {
  cout << "Yes" << endl;
  exit(0);
}

void No() {
  cout << "No" << endl;
  exit(0);
}
int main() {
  ll N;
  cin >> N;
  ll Q;
  cin >> Q;
  string S;
  cin >> S;
  ll L[Q];
  ll R[Q];
  rep(i, Q) {
    ll a, b;
    cin >> a >> b;
    L[i] = a;
    R[i] = b;
  }

  vector<ll> A;
  rep(i, N - 1) {
    if (S[i] == 'A' && S[i + 1] == 'C')
      A.push_back(i);
    else
      continue;
  }

  ll count = 0;
  ll count1 = 0;
  ll B[N];
  rep(i, N) { B[i] = 0; }
  rep(i, N) {
    if (A.empty())
      break;
    B[i] = count;
    if (A[count1] == i) {
      count++;
      count1++;
    }
  }

  rep(i, Q) {
    ll a = L[i] - 1;
    ll b = R[i] - 1;
    ll ans = B[b] - B[a];
    cout << ans << endl;
  }
}