Diagonal Difference

Diagonal Difference.js

process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var n = parseInt(readLine());
    var a = [];

    var a_sum = 0;
    var b_sum = 0;

    for(a_i = 0; a_i < n; a_i++){
       a[a_i] = readLine().split(' ');
       a[a_i] = a[a_i].map(Number);
    }
    
    for(i=0; i < n; i++){
        a_sum = a_sum + a[i][i];
        b_sum = b_sum + a[n-i-1][i];
    }
    
    var total = Math.abs(a_sum - b_sum);
    console.log(total);

 // a = (0,0) + (1,1) + (2,2) ( x+1, y+1 증가)
 // b = (0,2) + (1,1) + (2,0) ( x+1, y-1 증가)
}