不懂就问

#include<bits/stdc++.h>
using namespace std;
const int N = 1e6+5;
int a[N],n,mx;
map<int,int> mp;
int main(){
    cin>>n;
    for(int i = 0;i<n;i++){
        cin>>a[i];
        mp[a[i]]++;
        if(mp[a[i]]>=n/2){
            cout<<a[i]<<endl;
            return 0;
        }
    }
    cout<<"No"<<endl;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
const int N = 1e6+5;
int a[N],n;
int main(){
    cin>>n;
    for(int i = 0;i<n;i++){
        cin>>a[i];
    }
    sort(a,a+n);
    int cnt = 1;
    for(int i = 0;i<n-1;i++){
        if(a[i] == a[i+1])
            cnt++;
        else{
            if(cnt>=n/2){
                cout<<a[i]<<endl;
                return 0;
            }
            cnt = 1;
        }
    }
    cout<<"No"<<endl;
    return 0;
}