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find insert index in a sorted array
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| /** | |
| * Implements in place binary search. O(log n) | |
| * optional comparator can be passed | |
| */ | |
| function findInsertIndex(a, item, smaller) { | |
| var l = 0, | |
| len = a.length, | |
| r = len - 1, | |
| m; | |
| smaller = smaller || function(a, b, strict){ | |
| return strict ? a < b : a <= b; | |
| }; | |
| if (len === 0) return 0 | |
| while (true) { | |
| if (smaller(item, a[l], true)) return l; | |
| if (smaller(a[r], item, true)) return r+1; | |
| if (l === r-1 && smaller(a[l], item) && smaller(item, a[r])) return r | |
| m = Math.floor((r + l) / 2); | |
| if (item <= a[m]) r = m | |
| else l = m | |
| } | |
| } |
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