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Matrix Diagonal Sum

Easy
matrix array math
Problem Description

Calculate sum of both diagonals in a square matrix. Count center element only once if matrix size is odd.

Input Format
First line contains n. Next n lines contain matrix rows.
Output Format
Sum of both diagonals
Constraints
1 ≤ n ≤ 100, matrix elements ≤ 1000
Sample Input/Output
Input: 
3
1 2 3
4 5 6
7 8 9
Output: 
25
Explanation

Primary diagonal: 1+5+9=15, Secondary: 3+5+7=15, Center 5 counted once: 15+15-5=25

Solution Hints
  • Read carefully: Understand input/output format and constraints
  • Start simple: Think of brute force solution first, then optimize
  • Edge cases: Consider empty inputs, single elements, max constraints
  • Data structures: Choose arrays, hash maps, sets based on problem needs
  • Time complexity: Ensure your solution fits within time limits
  • Test examples: Verify logic with provided sample inputs
90
Points
2000ms
Time Limit
256MB
Memory Limit
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