Examples with coffeescript

coffee vs.js

### The implementation of binary search that is tested.

# Return the index of an element in a sorted list. (or -1, if not present)###
index = (list, target) ->
  [low, high] = [0, list.length]
  while low < high
    mid = (low + high) >> 1
    val = list[mid]
    return mid if val is target
    if val < target then low = mid + 1 else high = mid
  return -1

console.log 2 is index [10, 20, 30, 40, 50], 30
console.log 4 is index [-97, 35, 67, 88, 1200], 1200
console.log 0 is index [0, 45, 70], 0

_______________________________________________________

/* The implementation of binary search that is tested.

 * Return the index of an element in a sorted list. (or -1, if not present)
 */
var index;

index = function(list, target) {
  var high, low, mid, ref, val;
  ref = [0, list.length], low = ref[0], high = ref[1];
  while (low < high) {
    mid = (low + high) >> 1;
    val = list[mid];
    if (val === target) {
      return mid;
    }
    if (val < target) {
      low = mid + 1;
    } else {
      high = mid;
    }
  }
  return -1;
};

console.log(2 === index([10, 20, 30, 40, 50], 30));
console.log(4 === index([-97, 35, 67, 88, 1200], 1200));
console.log(0 === index([0, 45, 70], 0));