Language: C++

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

#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define REPr(i, n) for(int i = (n)-1; i >= 0; --i)
#define FORq(i, m, n) for(int i = (m); i <= (n); ++i)
#define FORqr(i, m, n) for(int i = (n); i >= (m); --i)
#define PB push_back
#define MP make_pair
#define fst first
#define snd second
#define SIN(x, S) (S.count(x) != 0)
#define M0(x) memset(x, 0, sizeof(x))
#define FILL(x, y) memset(x, y, sizeof(x))
#define MM(x) memset(x, -1, sizeof(x))
#define ALL(x) (x).begin(), (x).end()
#define DB(x) cerr << #x << " = " << x << endl
#define DB2(x, y)                                                              \
    cerr << "(" << #x << ", " << #y << ") = (" << x << ", " << y << ")\n";
#define DEBUG                                                                  \
    int x12345;                                                                \
    cin >> x12345;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<long long> VL;
typedef long long ll;
typedef long long integer;
///////////////////////////////////////////////
const ll MOD = 1e9 + 7;
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }

template <class T> inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T> inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}

template <int MOD> struct Fp {
    long long val;

    constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
        if(val < 0)
            v += MOD;
    }

    constexpr int getmod() { return MOD; }

    constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; }

    constexpr Fp operator+(const Fp &r) const noexcept {
        return Fp(*this) += r;
    }

    constexpr Fp operator-(const Fp &r) const noexcept {
        return Fp(*this) -= r;
    }

    constexpr Fp operator*(const Fp &r) const noexcept {
        return Fp(*this) *= r;
    }

    constexpr Fp operator/(const Fp &r) const noexcept {
        return Fp(*this) /= r;
    }

    constexpr Fp &operator+=(const Fp &r) noexcept {
        val += r.val;
        if(val >= MOD)
            val = val % MOD;
        return *this;
    }

    constexpr Fp &operator-=(const Fp &r) noexcept {
        val -= r.val;
        if(val < 0)
            val += MOD * ((-val + MOD - 1) / MOD);
        val = val % MOD;
        return *this;
    }

    constexpr Fp &operator*=(const Fp &r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }

    constexpr Fp &operator/=(const Fp &r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while(b) {
            long long t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        val = val * u % MOD;
        if(val < 0)
            val += MOD;
        return *this;
    }

    constexpr bool operator==(const Fp &r) const noexcept {
        return this->val == r.val;
    }

    constexpr bool operator!=(const Fp &r) const noexcept {
        return this->val != r.val;
    }

    friend constexpr ostream &operator<<(ostream &os,
                                         const Fp<MOD> &x) noexcept {
        return os << x.val;
    }

    friend constexpr istream &operator>>(istream &is, Fp<MOD> &x) noexcept {
        return is >> x.val;
    }

    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
        if(n == 0)
            return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if(n & 1)
            t = t * a;
        return t;
    }
};

using mint = Fp<MOD>;

///////////////////////////////////////////////
/// 🍈( '-' 🍈 |AC|
bool intersect(int a, int b, int C){
    if (a + C < b) return true;
    else false;
}

int main() {
    int N,K,C; cin >> N >> K >> C;
    string S; cin >> S;
    vector<int> Lg,Rg;
    vector<int> ans;
    int count1 = 0;
    int count2 = 0;
    REP(i,N){
        char c = S[i];
        if (c == 'o'){
            if (count1 < K) Lg.push_back(i);
            count1++;
            i = i + C;
        }
    }

    REPr(i,N){
        char c = S[i];
        if (c == 'o'){
            if (count2 < K) Rg.push_back(i);
            count2++;
            i = i - C;
        }
    }

    reverse(ALL(Rg));

    REP(i,K){
        if (Lg[i] == Rg[i]) ans.push_back[Lg[i] + 1];
    }
    // int cnt1 = 0;
    // int cnt2 = 0;
    // while((cnt1 < K) and (cnt2 < K)){
    //     if (Lg[cnt1] < Rg[cnt2]) cnt1++;
    //     else if (Lg[cnt1] > Rg[cnt2]) cnt2++;
    //     else{
    //         ans.push_back(Lg[cnt1]);
    //         cnt1++;
    //         cnt2++;
    //     }
    // }

    REP(i,ans.size()){
        cout << ans[i] << "\n";
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:179:42: error: invalid types '<unresolved overloaded function type>[__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type {aka int}]' for array subscript
  179 |         if (Lg[i] == Rg[i]) ans.push_back[Lg[i] + 1];
      |                                          ^
a.cc: In function 'bool intersect(int, int, int)':
a.cc:149:1: warning: control reaches end of non-void function [-Wreturn-type]
  149 | }
      | ^