Language: C++

#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=n-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define all(x) (x).begin(),(x).end()
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={1,0,-1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
using Graph = vector<vector<int>>;
double nCk(ll n, ll k) {
double res=1.0;
for(ll i=0; i<n; i++){
res*=0.5;}
for(ll i=0; i<k; i++){
res*=(double)(n-i);
res/=(double)(k-i);
}
return res;}
struct edge{ll to, cost;};
typedef pair<ll,ll> P;
struct graph{
  ll V;
  vector<vector<edge> > G;
  vector<ll> d;

  graph(ll n){
    init(n);
  }

  void init(ll n){
    V = n;
    G.resize(V);
    d.resize(V);
    rep(i,V){
      d[i] = INF;
    }
  }

  void add_edge(ll s, ll t, ll cost){
    edge e;
    e.to = t, e.cost = cost;
    G[s].push_back(e);
  }

  void dijkstra(ll s){
    rep(i,V){
      d[i] = INF;
    }
    d[s] = 0;
    priority_queue<P,vector<P>, greater<P> > que;
    que.push(P(0,s));
    while(!que.empty()){
      P p = que.top(); que.pop();
      ll v = p.second;
      if(d[v]<p.first) continue;
      for(auto e : G[v]){
        if(d[e.to]>d[v]+e.cost){
          d[e.to] = d[v]+e.cost;
          que.push(P(d[e.to],e.to));
        }
      }
    }
  }
};
class UnionFind
{
public:
  ll par[100005];
  ll depth[100005];
  ll nGroup[100005];
 
  UnionFind(ll n) {
    init(n);
  }
 
  void init(ll n) {
    for(ll i=0; i<n; i++) {
      par[i] = i;
      depth[i] = 0;
      nGroup[i] = 1;
    }
  }
 
  ll root(ll x) {
    if(par[x] == x) {
      return x;
    } else {
      return par[x] = root(par[x]);
    }
  }
 
  bool same(ll x, ll y) {
    return root(x) == root(y);
  }
 
  void unite(ll x, ll y) {
    x = root(x);
    y = root(y);
    if(x == y) return;
 
    if(depth[x] < depth[y]) {
      par[x] = y;
      nGroup[y] += nGroup[x];
      nGroup[x] = 0;
    } else {
      par[y] = x;
      nGroup[x] += nGroup[y];
      nGroup[y] = 0;
      if(depth[x] == depth[y])
        depth[x]++;
    }
  }
};
const ll MAX = 500010;
ll fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}
vector<ll> depth;
vector<ll> f;
vector<ll> g;
void dfs(const Graph &G, ll v, ll p, ll d) {
    depth[v] = d;
    for (auto nv : G[v]) {
        if (nv == p) continue; // nv が親 p だったらダメ
        dfs(G, nv, v, d+1);
    }

    // 帰りがけ時に、部分木サイズを求める
    f[v] = 1;
    g[v] = 1;// 自分自身
    for (auto c : G[v]) {
        if (c == p) continue;
        f[v]*=g[c];
        f[v]%=MOD;
        g[v]*=f[c];
        g[v]%=MOD;
        }
    f[v]+=g[v];
    f[v]%=MOD;
}
template<ll MOD> struct Fp {
    ll val;
    constexpr Fp(ll v = 0) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr ll 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 -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) 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 {
        ll a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            ll 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 Fp<MOD> modpow(const Fp<MOD> &a, ll 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>;

mint calc(ll N, ll K) {
    mint res = 1;
    for (ll n = 0; n < K; ++n) {
        res *= (N - n);
        res /= (n + 1);
    }
    return res;
}
mint COM(ll n, ll k){
    if (k == 0) return 1;
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
} 
int main() {
ll n; cin>>n;
if(n%2==0||n%5==0){
cout << -1 << endl;}
else{
ll ca = 0;
ll ans = 0;
for(ll i=1; i<n; i++){
if(s.at(i)=='R')ca++;}
for(ll i=0; i<ca; i++){
if(s.at(i)=='W')ans++;}
cout << ans << end


Compiler output:
a.cc: In function 'int main()':
a.cc:242:4: error: 's' was not declared in this scope
  242 | if(s.at(i)=='R')ca++;}
      |    ^
a.cc:244:4: error: 's' was not declared in this scope
  244 | if(s.at(i)=='W')ans++;}
      |    ^
a.cc:245:13: error: no match for 'operator<<' (operand types are 'std::basic_ostream<char>::__ostream_type' {aka 'std::basic_ostream<char>'} and '<unresolved overloaded function type>')
  245 | cout << ans << end
      | ~~~~~~~~~~~~^~~~~~
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/ostream:116:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ostream_type& (*)(__ostream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  116 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/ostream:116:36: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'std::basic_ostream<char>::__ostream_type& (*)(std::basic_ostream<char>::__ostream_type&)' {aka 'std::basic_ostream<char>& (*)(std::basic_ostream<char>&)'}
  116 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/ostream:125:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>; __ios_type = std::basic_ios<char>]'
  125 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/ostream:125:32: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'std::basic_ostream<char>::__ios_type& (*)(std::basic_ostream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  125 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/14/ostream:135:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  135 |       operator<<(ios_base& (*__pf) (ios_base&))
      |       ^~~~~~~~
/usr/include/c++/14/ostream:135:30: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'std::ios_base& (*)(std::ios_base&)'
  135 |       operator<<(ios_base& (*__pf) (ios_base&))
      |                  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/usr/include/c++/14/ostream:174:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  174 |       operator<<(long __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:174:23: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'long int'
  174 |       operator<<(long __n)
      |                  ~~~~~^~~
/usr/include/c++/14/ostream:178:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  178 |       operator<<(unsigned long __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:178:32: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'long unsigned int'
  178 |       operator<<(unsigned long __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/ostream:182:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  182 |       operator<<(bool __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:182:23: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'bool'
  182 |       operator<<(bool __n)
      |                  ~~~~~^~~
In file included from /usr/include/c++/14/ostream:1022:
/usr/include/c++/14/bits/ostream.tcc:96:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char; _Traits = std::char_traits<char>]'
   96 |     basic_ostream<_CharT, _Traits>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/ostream.tcc:97:22: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'short int'
   97 |     operator<<(short __n)
      |                ~~~~~~^~~
/usr/include/c++/14/ostream:189:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  189 |       operator<<(unsigned short __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:189:33: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'short unsigned int'
  189 |       operator<<(unsigned short __n)
      |                  ~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ostream.tcc:110:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char; _Traits = std::char_traits<char>]'
  110 |     basic_ostream<_CharT, _Traits>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/ostream.tcc:111:20: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'int'
  111 |     operator<<(int __n)
      |                ~~~~^~~
/usr/include/c++/14/ostream:200:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  200 |       operator<<(unsigned int __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:200:31: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'unsigned int'
  200 |       operator<<(unsigned int __n)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/14/ostream:211:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  211 |       operator<<(long long __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:211:28: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'long long int'
  211 |       operator<<(long long __n)
      |                  ~~~~~~~~~~^~~
/usr/include/c++/14/ostream:215:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  215 |       operator<<(unsigned long long __n)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:215:37: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'long long unsigned int'
  215 |       operator<<(unsigned long long __n)
      |                  ~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/ostream:231:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  231 |       operator<<(double __f)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:231:25: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'double'
  231 |       operator<<(double __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/ostream:235:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  235 |       operator<<(float __f)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:235:24: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'float'
  235 |       operator<<(float __f)
      |                  ~~~~~~^~~
/usr/include/c++/14/ostream:243:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  243 |       operator<<(long double __f)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:243:30: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'long double'
  243 |       operator<<(long double __f)
      |                  ~~~~~~~~~~~~^~~
/usr/include/c++/14/ostream:301:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  301 |       operator<<(const void* __p)
      |       ^~~~~~~~
/usr/include/c++/14/ostream:301:30: note:   no known conversion for argument 1 from '<unresolved overloaded function type>' to 'const void*'
  301 |       operator<<(const void* __p)
      |                  ~~~~~~~~~~~~^~~
/usr/include/c++/14/ostream:306:7: note: candidate: 'std::basic_ostream<_Cha