Can anyone tell me what is wrong in my code?

general
1

que- MEX ARRay

code:

include <bits/stdc++.h>
using namespace std;
define int long long
const unsigned int M = 1000000007;

int32_t main() {
// your code goes here

ios_base::sync_with_stdio(false);
cin.tie(NULL);

int t;
cin>>t;
while(t--){

    int n;
    cin>>n;
    
    int N = 2*100000 + 2;
    
    vector<int> v(N,0);
    
    for(int i=0;i<n;i++){
        int t;
        cin>>t;
        v[t]++;
    }
    
    if(v[0]==0){
        cout<<1<<endl;
        cout<<0<<endl;
    }
    else{
        int curr=v[0];
        int ind;
        for(int i=1;i<N;i++){
            if(v[i]==0){
                ind=i;
                break;
            }
            curr = min(curr,v[i]);
            v[i] = v[i]-curr;
        }
        int r=0;
        for(int i=1;i<N;i++){
            if(v[i]>0){
                r++;
                break;
            }
        }
        int size=curr+r;
        cout<<size<<endl;
        for(int i=0;i<curr;i++){
            cout<<ind<<" ";
        }
        if(r>0){
            cout<<0<<endl;
        }
    }
    

}
return 0;

}

3

Well, there is an error in for loop, you can replace your code by below code:

#include <iostream>
#include <vector>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;

        int N = 2 * 100000 + 2;

        vector<int> v(N, 0);

        for (int i = 0; i < n; i++) {
            int t;
            cin >> t;
            v[t]++;
        }

        if (v[0] == 0) {
            cout << 1 << endl;
            cout << 0 << endl;
        } else {
            int curr = v[0];
            int ind = -1;  // Initialize ind to a default value
            for (int i = 1; i < N; i++) {
                if (v[i] == 0) {
                    ind = i;
                    break;
                }
                curr = min(curr, v[i]);
                v[i] = v[i] - curr;
            }
            int r = 0;
            for (int i = 1; i < N; i++) {
                if (v[i] > 0) {
                    r++;
                    break;
                }
            }
            int size = curr + r;
            cout << size << endl;
            for (int i = 0; i < curr; i++) {
                cout << ind << " ";
            }
            if (r > 0) {
                cout << 0 << endl;
            }
        }
    }
    return 0;
}

I hope it is clear now.
Thanks