Submission #73724631

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

// --- Type Definitions ---
using ll = long long;
using db = long double; // Crucial for those "Lantern" precision problems
using str = string;

// --- Vectors & Pairs ---
using pi = pair<int,int>;
using pl = pair<ll,ll>;
using vi = vector<int>;
using vl = vector<ll>;

// --- Shortcuts ---
#define mp make_pair
#define f first
#define pb push_back
#define eb emplace_back // Slightly faster than pb
#define all(x) begin(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define sz(x) int((x).size())

// --- Loops ---
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define each(a,x) for (auto& a: x)

// --- Input/Output Optimization ---
void setIO(string name = "") {
    cin.tie(0)->sync_with_stdio(0); // Fast I/O
    if (sz(name)) {
        freopen((name + ".in").c_str(), "r", stdin); 
        freopen((name + ".out").c_str(), "w", stdout);
    }
    // Auto-fix precision for doubles (stops 2.5 becoming 2.5e+00)
    cout << fixed << setprecision(15);
}

// --- Constant ---
const ll MOD = 1e9+7; // For those "modulo 10^9+7" problems
const ll INF = 1e18;  // Huge number for infinity

int main() {
    setIO(); 
    str s; cin >> s;
 
    int a = 0, ab = 0, res = 0;

    each(c, s) {
        if (c== 'A') {
            a++;
        } else if (c== 'B') {
            if (a > 0) {
              a--;
                ab++;
            }
        } else if (c =='C') {
          if (ab>0) {
              ab--;
              res++;
          }
        }
    }

  cout<<res;
}

Submission Info

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