Language: C++

#include <iostream>
#include <cassert>
#include <climits>
#include <bitset>
#include <stack>
#include <queue>
#include <iomanip>
#include <limits>
#include <string>
#include <cmath>
#include <set>
#include <map>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string.h>
#include <tuple>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;

long long int INF = 3e18;
double Pi = 3.1415926535897932384626;

vector<ll> G[500005];
vector<P> tree[500010];
priority_queue <ll> pql;
priority_queue <P> pqp;
//big priority queue
priority_queue <ll,vector<ll>,greater<ll> > pqls;
priority_queue <P,vector<P>,greater<P> > pqps;
//small priority queue
//top pop

int dx[8]={1,0,-1,0,1,1,-1,-1};
int dy[8]={0,1,0,-1,1,-1,-1,1};
char dir[] = "DRUL";
//ll bit[500005];
//↓,→,↑,←


#define p(x) cout<<x<<endl;
#define el cout<<endl;
#define pe(x) cout<<(x)<<" ";
#define ps(x) cout<<fixed<<setprecision(25)<<x<<endl;
#define pu(x) cout<<(x);
#define pd(x) cerr<<(x)<<endl;
#define re(i,n) for(i=0;i<n;i++);
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define deba(x) cout<< #x << " = " << x <<endl


ll mod = 1000000007;
ll rui(ll number1,ll number2){
    if(number2 == 0){
        return 1;
    }else{
        ll number3 = rui(number1,number2 / 2);
        number3 *= number3;
        number3 %= mod;
        if(number2%2==1){
            number3 *= number1;
            number3 %= mod;
        }
        return number3;
    }
}
ll gcd(ll number1,ll number2){
    if(number1 > number2){
        swap(number1,number2);
    }
    if(number1 == 0 || number1 == number2){
        return number2;
    }else{
        return gcd(number2 % number1,number1);
    }
}
void YES(bool condition){
    if(condition){
        p("YES");
    }else{
        p("NO");
    }
    return;
}
void Yes(bool condition){
    if(condition){
        p("Yes");
    }else{
        p("No");
    }
    return;
}

ll n,m,num,sum,ans,a,b,c,d,e,f,g,h,i,j,k,w,ok,ng,l,q;
ll x[500005],y[500005],z[500005];
char s[500005],t[500005];
bool flag,dame;

bool whitecount(ll v,ll p){
	if(s[v-1] == 'W'){
		return true;
	}else{
		bool flag = false;
		for(int i=0;i<G[v].size();i++){
			if(whitecount(G[v][i],v))flag = true;
		}
		return flag;
	}
}
ll oneway(ll v,ll p){
	return 0;
}
ll twoway(ll v,ll p){
	return 0;
}

void solve(ll v){
	ll white = 0;
	vector<ll> p;
	for(int i=0;i<G[v].size();i++){
		if(whitecount(G[v][i],v)){
			white++;
			p.pb(G[v][i]);
		}
	}
	if(white == 0){
		if(s[v-1] == 'W'){
			p(1);
			return;
		}else{
			p(0);
			return;
		}
	}else if(white == 1){
		p(oneway(p[0],v));
	}else if(white == 2){
		p(oneway(p[0],v) + oneway(p[1],v));
	}else{



int main(){
    cin >> n;
	return 0;
	for(i=0;i<n-1;i++){
		cin >> a >> b;
		G[a].pb(b);
		G[b].pb(a);
	}
	solve(1);
	return 0;
}

Compiler output:
a.cc: In function 'void solve(ll)':
a.cc:147:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
  147 | int main(){
      |         ^~
a.cc:147:9: note: remove parentheses to default-initialize a variable
  147 | int main(){
      |         ^~
      |         --
a.cc:147:9: note: or replace parentheses with braces to value-initialize a variable
a.cc:147:11: error: a function-definition is not allowed here before '{' token
  147 | int main(){
      |           ^
a.cc:157:2: error: expected '}' at end of input
  157 | }
      |  ^
a.cc:143:14: note: to match this '{'
  143 |         }else{
      |              ^
a.cc:157:2: error: expected '}' at end of input
  157 | }
      |  ^
a.cc:122:17: note: to match this '{'
  122 | void solve(ll v){
      |                 ^