@bazilio-san/af-stream
Version:
Data stream from database table
128 lines • 3.58 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.findSlotInt = exports.findSlotIntBINARY = exports.findSlotIntRIGHT = exports.findSlotIntLEFT = void 0;
const findSlotIntLEFT = (arr, x) => {
const lastIndex = arr.length - 1;
if (lastIndex < 0) {
return [null, null, null];
}
const index = arr.findIndex((v) => v >= x);
if (index > -1) {
if (arr[index] === x) {
return [
index === 0 ? null : index - 1,
index,
index === lastIndex ? null : index + 1,
];
} // x < arr[index]
return [
index === 0 ? null : index - 1,
null,
index,
];
}
// index === -1: X больше наибольшего
return [lastIndex, null, null];
};
exports.findSlotIntLEFT = findSlotIntLEFT;
const findSlotIntRIGHT = (arr, x) => {
const { length } = arr;
if (!length) {
return [null, null, null];
}
let pos = length;
const lastIndex = length - 1;
while (--pos >= 0) {
const v = arr[pos];
if (v === x) {
return [
pos === 0 ? null : pos - 1,
pos,
pos === lastIndex ? null : pos + 1,
];
}
if (v < x) {
return [
pos,
null,
pos === lastIndex ? null : pos + 1,
];
}
}
return [null, null, 0];
};
exports.findSlotIntRIGHT = findSlotIntRIGHT;
const findSlotIntBINARY = (arr, x) => {
const { length } = arr;
if (!length) {
return [null, null, null];
}
const lastIndex = length - 1;
let start = 0;
let end = length;
if (x < arr[0]) {
return [null, null, 0];
}
if (x === arr[0]) {
return [null, 0, length > 1 ? 1 : null];
}
if (x > arr[lastIndex]) {
return [lastIndex, null, null];
}
if (x === arr[lastIndex]) {
return [lastIndex ? lastIndex - 1 : null, lastIndex, null];
}
let mid = 0;
while (start <= end) {
mid = Math.floor((start + end) / 2);
if (arr[mid] === x) {
return [
mid === 0 ? null : mid - 1,
mid,
mid === length - 1 ? null : mid + 1,
];
}
if (arr[mid] > x) {
end = mid - 1;
}
else {
start = mid + 1;
}
}
if (arr[mid] < x) {
return [
mid,
null,
length > 1 ? mid + 1 : null,
];
}
return [
length > 1 ? mid - 1 : null,
null,
mid,
];
};
exports.findSlotIntBINARY = findSlotIntBINARY;
/**
* Searches for a place for an integer (x) in an array of integers (arr) sorted in ascending order.
* Returns an array of 3 indices:
[
<index of nearest smaller number | null>,
<index of number equal to desired | null>,
<index of nearest larger number | null>
]
*/
const findSlotInt = (arr, x) => {
const { length } = arr;
if (!length) {
return [null, null, null];
}
if (length > 2000) {
return (0, exports.findSlotIntBINARY)(arr, x);
}
return ((arr[length - 1] - arr[0]) / 2) < x
? (0, exports.findSlotIntRIGHT)(arr, x)
: (0, exports.findSlotIntLEFT)(arr, x);
};
exports.findSlotInt = findSlotInt;
//# sourceMappingURL=find-slot-int.js.map