Expected Time Complexity: O(N)

Expected Auxiliary Space: O(1)


Constraints:
1 <= N <= 10^5
0 <= A[i] <= 2


//Here we have a function


1:  void sort012(int a[], int n)  
2:  {  
3:    int c0=0,c1=0,c2=0;  
4:    c0=count(a,a+n,0);  
5:    c1=count(a,a+n,1);  
6:    c2=count(a,a+n,2);  
7:    int k=0;  
8:    for(int i=0;i<c0;i++)  
9:    a[k++]=0;  
10:    for(int i=0;i<c1;i++)  
11:    a[k++]=1;  
12:    for(int i=0;i<c2;i++)  
13:    a[k++]=2;  
14:  }


//Here we have a full program.

  
1:  #include <bits/stdc++.h>  
2:  using namespace std;  
3:  int main()  
4:  {  
5:    int arr[5];  
6:    int n = 5;  
7:    for(int i = 0 ; i < 5; i++)  
8:    cin>>arr[i];  
9:    int c0=0,c1=0,c2=0;  
10:    count(a,a+n,0);  
11:    count(a,a+n,1);  
12:    count(a,a+n,2);  
13:    int k =0 ;  
14:    for(int i = 0 ; i < c0 ; i++)arr[k++] = 0;  
15:    for(int i = 0 ; i < c1 ; i++)arr[k++] = 1;  
16:    for(int i = 0 ; i < c2 ; i++)arr[k++] = 2;  
17:    for(int i = 0 ; i < n ; i++)  
18:    cout<<arr[i]<<endl;  
19:    return 0;  
20:  }