corrected return value

contents/thomas_algorithm/code/javascript/thomas.js

@@ -1,19 +1,20 @@
 function thomas(a, b, c, x) {
+ const result = [];
  const y = [];
 
  y[0] = c[0] / b[0];
- x[0] = x[0] / b[0];
+ result[0] = x[0] / b[0];
 
  for (let i = 1; i < a.length; i++) {
  const scale = 1 / (b[i] - a[i] * y[i - 1]);
  y[i] = c[i] * scale;
- x[i] = (x[i] - a[i] * x[i - 1]) * scale;
+ result[i] = (x[i] - a[i] * result[i - 1]) * scale;
  }
 
  for (let i = a.length - 2; i >= 0; i--)
- x[i] -= y[i] * x[i + 1];
+ result[i] -= y[i] * result[i + 1];
 
- return x;
+ return result;
 }
 
 let a = [0, 2, 3];