Control C401A P64789


Statement
 

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Your task is to write a program that reads a sequence of square matrices of integers, and for each one prints the sum of the numbers which are in their two diagonals.

Usign the definition

typedef vector<vector<int> > Matrix;

your program must implement and use the function

int sum_diagonals(const Matrix& mat);

that returns the sum of the numbers in the diagonals of the square matrix and non empty |mat|.

Input

The input consists of a sequence of cases. Each case starts with the size n ≥ 1 of the matrix, followed by n lines, each one with the n integers of the corresponding row.

Output

For each matrix, print a line with the sum of the numbers which are in its diagonals.

Public test cases
  • Input

    1
    7
    
    2
    1 2
    3 4
    
    3
     1   3   0
     5   2   7
    -8  -4  -9
    
    4
    1000000          3          4   -1000000
          1   -1000000    1000000          7
          2   -1000000    1000000          8
    1000000          5          6   -1000000
    

    Output

    7
    10
    -14
    0
    
  • Input

    5
    11 22 33 46 15
    41 33 94 58 71
    56 23 45 98 21
    54 15 37 26 17
    65 88 99 66 11
    

    Output

    279
    
  • Information
    Author
    Professorat de P1
    Language
    English
    Translator
    Carlos Molina
    Original language
    Catalan
    Other languages
    Catalan
    Official solutions
    C++
    User solutions
    C++