Language: C++

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define OP ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define F first
#define S second
#define sz(x) (int)x.size()
#define all(x) (x).begin(), (x).end()
#define rep(i, n) for(int i = 0; i < n; ++i)
#define repr(i,n) for(int i = n - 1; i >= 0; --i)
#define Rep(i, a, n) for(int i = (a); i <=(n); ++i)
#define repst(i, n) for(auto it = n.begin(); it != n.end(); ++it)
#define Repr(i, a, n) for(int i = (n); i >= (a); --i)
typedef long long ll;
typedef std::vector<int> vi;
typedef std::pair<int, int> pii;
const int inf = int(1e9);
const int mod = inf + 7;
const double PI = acos(-1.0);
using namespace std;
const int N = 1e5 + 155;
template<typename T>
inline void read(T&x){
    x=0;int f=1;char ch = getchar();
    while(ch<'0' ||ch>'9'){ if(ch=='-')f=-1;ch=getchar(); }
    while(ch>='0' && ch<='9'){ x=x*10+ch-'0'; ch=getchar(); }
    x*=f;
}
 
 
ll bp(ll a, ll n){
	ll r = 1;
	while(n){
		if(n & 1) r = (r * a) % mod;
		a = (a * a) % mod;
		n >>= 1;
	}
	return r;
}

 
void solve(){
	string s;
	cin >> s;
	unordered_map<char, int> m;
	for(char c: s) m[s]++;
	for(auto it: m) {
		if (it.second % 2) {
			cout << "No";
			return;
		}
	}
	cout << "Yes";
}

int main(){
    OP
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    int t = 1;
	//cin >> t;
    for(int i = 1; i <= t; i++) {
        solve();
    }
    return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:46:25: error: no match for 'operator[]' (operand types are 'std::unordered_map<char, int>' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   46 |         for(char c: s) m[s]++;
      |                         ^
In file included from /usr/include/c++/14/unordered_map:41,
                 from /usr/include/c++/14/functional:63,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/unordered_map.h:987:7: note: candidate: 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type& std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type&) [with _Key = char; _Tp = int; _Hash = std::hash<char>; _Pred = std::equal_to<char>; _Alloc = std::allocator<std::pair<const char, int> >; mapped_type = int; key_type = char]'
  987 |       operator[](const key_type& __k)
      |       ^~~~~~~~
/usr/include/c++/14/bits/unordered_map.h:987:34: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'const std::unordered_map<char, int>::key_type&' {aka 'const char&'}
  987 |       operator[](const key_type& __k)
      |                  ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/unordered_map.h:991:7: note: candidate: 'std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::mapped_type& std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](key_type&&) [with _Key = char; _Tp = int; _Hash = std::hash<char>; _Pred = std::equal_to<char>; _Alloc = std::allocator<std::pair<const char, int> >; mapped_type = int; key_type = char]'
  991 |       operator[](key_type&& __k)
      |       ^~~~~~~~
/usr/include/c++/14/bits/unordered_map.h:991:29: note:   no known conversion for argument 1 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'std::unordered_map<char, int>::key_type&&' {aka 'char&&'}
  991 |       operator[](key_type&& __k)
      |                  ~~~~~~~~~~~^~~