|
| 1 | +// Constant runtime - Big O Notation: "O (1)" |
| 2 | +function log(array) { |
| 3 | + console.log(array[0]); |
| 4 | + console.log(array[1]); |
| 5 | +} |
| 6 | + |
| 7 | +log([1, 2, 3, 4]); |
| 8 | +log([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]); |
| 9 | + |
| 10 | +// Linear runtime - Big O Notation: "O (n)" |
| 11 | +function logAll(array) { |
| 12 | + for (var i = 0; i < array.length; i++) { |
| 13 | + console.log(array[i]); |
| 14 | + } |
| 15 | +} |
| 16 | + |
| 17 | +logAll([1, 2, 3, 4, 5]); |
| 18 | +logAll([1, 2, 3, 4, 5, 6]); |
| 19 | +logAll([1, 2, 3, 4, 5, 6, 7]); |
| 20 | + |
| 21 | +// Exponential runtime - Big O Notation: "O (n^2)" |
| 22 | +function addAndLog(array) { |
| 23 | + for (var i = 0; i < array.length; i++) { |
| 24 | + for (var j = 0; j < array.length; j++) { |
| 25 | + console.log(array[i] + array[j]); |
| 26 | + } |
| 27 | + } |
| 28 | +} |
| 29 | + |
| 30 | +addAndLog(["A", "B", "C"]); // 9 pairs logged out |
| 31 | +addAndLog(["A", "B", "C", "D"]); // 16 pairs logged out |
| 32 | +addAndLog(["A", "B", "C", "D", "E"]); // 25 pairs logged out |
| 33 | + |
| 34 | +// Logarithmic runtime - Big O Notation: O (log n) |
| 35 | +function binarySearch(array, key) { |
| 36 | + var low = 0; |
| 37 | + var high = array.length - 1; |
| 38 | + var mid; |
| 39 | + var element; |
| 40 | + |
| 41 | + while (low <= high) { |
| 42 | + mid = Math.floor((low + high) / 2, 10); |
| 43 | + element = array[mid]; |
| 44 | + if (element < key) { |
| 45 | + low = mid + 1; |
| 46 | + } else if (element > key) { |
| 47 | + high = mid - 1; |
| 48 | + } else { |
| 49 | + return mid; |
| 50 | + } |
| 51 | + } |
| 52 | + return -1; |
| 53 | +} |
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