Print all numbers from 1 to n*n

Problem

Print all numbers from 1 to n^2 in ‘ㄹ’ shape

Example

input: 
4
5

output:
1 2 3 4
8 7 6 5 
9 10 11 12
16 15 14 13

1 2 3 4 5
10 9 8 7 6
11 12 13 14 15
20 19 18 17 16
21 22 23 24 25

written in C++

Solution 1

Use std::stack to store every even number line
Time Complexity = O(n)

void printMultiples(int n){
    stack reverseList;
    size_t line = 1;
    for(size_t i = 1; i <= n*n; ++i){
        if (line %2 == 0){
            reverseList.push((int)i);
        }else{
            cout << i << " ";
        }
        if (i%n == 0 && line %2 == 1){
            ++line;
            cout << "\n";
        }
        if (reverseList.size() == n){
            for(size_t j = 0; j < n; ++j){
                cout << reverseList.top() << " ";
                reverseList.pop();
            }
            cout << "\n";
        }
    }
}
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