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| 1 | +/*Binary Search-Search a sorted array by repeatedly dividing the search interval |
| 2 | +* in half. Begin with an interval covering the whole array. If the value of the |
| 3 | +* search key is less than the item in the middle of the interval, narrow the interval |
| 4 | +* to the lower half. Otherwise narrow it to the upper half. Repeatedly check until the |
| 5 | +* value is found or the interval is empty. |
| 6 | +*/ |
| 7 | + |
| 8 | +function binarySearch(arr, i) { |
| 9 | + var mid = Math.floor(arr.length / 2); |
| 10 | + if (arr[mid] === i) { |
| 11 | + console.log('match', arr[mid], i); |
| 12 | + return arr[mid]; |
| 13 | + } else if (arr[mid] < i && arr.length > 1) { |
| 14 | + binarySearch(arr.splice(mid, Number.MAX_VALUE), i); |
| 15 | + } else if (arr[mid] > i && arr.length > 1) { |
| 16 | + binarySearch(arr.splice(0, mid), i); |
| 17 | + } else { |
| 18 | + console.log('not found', i); |
| 19 | + return -1; |
| 20 | + } |
| 21 | + |
| 22 | +} |
| 23 | + |
| 24 | +var ar=[1,2,3,4,5,6,7,8,9,10]; |
| 25 | +binarySearch(ar,3); |
| 26 | +binarySearch(ar,7); |
| 27 | +binarySearch(ar,13); |
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