Hayden - Edges (C10) - Matrix CheckSum

lib/matrix_check_sum.rb

@@ -3,5 +3,30 @@
 # of numbers in row i is the same as the sum of numbers in column i for i = 0 to row.length-1
 # If this is the case, return true. Otherwise, return false.
 def matrix_check_sum(matrix)
-  raise NotImplementedError
+  per_line = matrix.length
+  col_index = 0
+
+  matrix.each do |row|
+    row_sum = 0
+    per_line.times do |i|
+      row_sum += row[i]
+    end
+
+    col_sum = 0
+    per_line.times do |i|
+      col_sum += matrix[i][col_index]
+    end
+
+    if row_sum == col_sum
+      col_index += 1
+    else
+      return false
+    end
+
+  end
+  return true
 end
+
+
+# the time complexity for this solution is O(n^2) because for each element in a column, it also has to iterate over each element in the corresponding row.
+# the space complexity is O(1) because the only memory required is a few iteration variables and the accumulators