Algorithm

Problem Name: Algorithms - Diagonal Difference

In this HackerRank Functions in Algorithms - Java programming problem solution,

Given a square matrix, calculate the absolute difference between the sums of its diagonals.

For example, the square matrix

is shown below:

1 2 3
4 5 6
9 8 9


The left-to-right diagonal = 1 + 5 + 9 = 15. The right to left diagonal = 3 + 5 + 9 = 17. Their absolute difference is |15 - 17| = 2

Function description

Complete the diagonalDifference function in the editor below.

diagonalDifference takes the following parameter:

• int arr[n][m]: an array of integers

Return

• int: the absolute diagonal difference

Input Format

The first line contains a single integer, n, the number of rows and columns in the square matrix arr.

Each of the next n lines describes a row, arr[i] , and consists of n space-separated integers arr [i][j]

Constraints

• -100 <= arr[i][j] <= 100

Output Format

Return the absolute difference between the sums of the matrix's two diagonals as a single integer.

Sample Input

3
11 2 4
4 5 6
10 8 -12


Sample Output

15


Explanation

The primary diagonal is:

11
5
-12


Sum across the primary diagonal: 11 + 5 - 12 = 4

The secondary diagonal is:

     4
5
10


Sum across the secondary diagonal: 4 + 5 + 10 = 19
Difference: |4 - 19| = 15

Note: |x| is the absolute value of x

Code Examples

#1 Code Example with C Programming

Code - C Programming


#include <stdio.h>
#include <stdlib.h>

int main() {
int n, k;
scanf("%d", &n);

int total = 0;
for (int i = 0; i  <  n; i++) {
for (int j = 0; j  <  n; j++) {
scanf("%d", &k);
if (i == j)
total += k;
if (i == n - j - 1)
total -= k;
}
}
printf("%d", abs(total));
return 0;
}

Copy The Code &

#2 Code Example with C++ Programming

Code - C++ Programming


#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector < string> split(const string &);

/*
* Complete the 'diagonalDifference' function below.
*
* The function is expected to return an INTEGER.
* The function accepts 2D_INTEGER_ARRAY arr as parameter.
*/

int diagonalDifference(vector<vector<int>> arr) {

int s1 = 0;
int s2 = 0;
int n = arr.size();

for(int i = 0; i  <  n; i++) {
s1 += arr[i][i];
s2 += arr[i][n-i-1];
}
return abs(s1 - s2);
}

int main()
{
ofstream fout(getenv("OUTPUT_PATH"));

string n_temp;
getline(cin, n_temp);

int n = stoi(ltrim(rtrim(n_temp)));

vector < vector<int>> arr(n);

for (int i = 0; i  <  n; i++) {
arr[i].resize(n);

string arr_row_temp_temp;
getline(cin, arr_row_temp_temp);

vector < string> arr_row_temp = split(rtrim(arr_row_temp_temp));

for (int j = 0; j  <  n; j++) {
int arr_row_item = stoi(arr_row_temp[j]);

arr[i][j] = arr_row_item;
}
}

int result = diagonalDifference(arr);

fout << result << "\n";

fout.close();

return 0;
}

string ltrim(const string &str) {
string s(str);

s.erase(
s.begin(),
find_if(s.begin(), s.end(), not1(ptr_fun < int, int>(isspace)))
);

return s;
}

string rtrim(const string &str) {
string s(str);

s.erase(
find_if(s.rbegin(), s.rend(), not1(ptr_fun < int, int>(isspace))).base(),
s.end()
);

return s;
}

vector < string> split(const string &str) {
vector<string> tokens;

string::size_type start = 0;
string::size_type end = 0;

while ((end = str.find(" ", start)) != string::npos) {
tokens.push_back(str.substr(start, end - start));

start = end + 1;
}

tokens.push_back(str.substr(start));

}

Copy The Code &

#3 Code Example with Java Programming

Code - Java Programming


import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

/*
* Complete the 'diagonalDifference' function below.
*
* The function is expected to return an INTEGER.
* The function accepts 2D_INTEGER_ARRAY arr as parameter.
*/

public static int diagonalDifference(List < List b) ? a - b : b - a;
}

}

public class Solution {
public static void main(String[] args) throws IOException {
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

List < List();

IntStream.range(0, n).forEach(i -> {
try {
.map(Integer::parseInt)
.collect(toList())
);
} catch (IOException ex) {
throw new RuntimeException(ex);
}
});

int result = Result.diagonalDifference(arr);

bufferedWriter.write(String.valueOf(result));
bufferedWriter.newLine();

bufferedWriter.close();
}
}

Copy The Code &

#4 Code Example with C# Programming

Code - C# Programming


using System;
using static System.Console;

class Solution
{

static void Main(String[] args)
{
var sumPrimaryDiagonal = 0;
var sumSecondaryDiagonal = 0;
for (int i = 0, j = n - 1; i  <  n; i++, j--)
{
var newRow = Array.ConvertAll(a_temp, int.Parse);
sumPrimaryDiagonal += newRow[i];
sumSecondaryDiagonal += newRow[j];
}
WriteLine(Math.Abs(sumPrimaryDiagonal - sumSecondaryDiagonal));
}
}

Copy The Code &

#5 Code Example with Python Programming

Code - Python Programming


import math
import os
import random
import re
import sys

# Complete the diagonalDifference function below.
def diagonalDifference(arr):
prim =0
sec=0
length = len(arr[0])
for count in range(length):
prim += arr[count][count]
sec += arr[count][(length-count-1)]
return abs(prim-sec)

if __name__ == '__main__':
fptr = open(os.environ['OUTPUT_PATH'], 'w')

n = int(input())

arr = []

for _ in range(n):
arr.append(list(map(int, input().rstrip().split())))

result = diagonalDifference(arr)

fptr.write(str(result) + '\n')

fptr.close()

Copy The Code &