92 lines
2.8 KiB
JavaScript
92 lines
2.8 KiB
JavaScript
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/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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/**
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* AUTO-GENERATED FILE. DO NOT MODIFY.
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*/
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/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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function defaultCompareFunc(a, b) {
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return a - b;
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}
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function swapElement(arr, idx0, idx1) {
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var tmp = arr[idx0];
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arr[idx0] = arr[idx1];
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arr[idx1] = tmp;
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}
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function select(arr, left, right, nth, compareFunc) {
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var pivotIdx = left;
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var pivotValue;
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while (right > left) {
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pivotIdx = Math.round((right + left) / 2);
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pivotValue = arr[pivotIdx];
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// Swap pivot to the end
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swapElement(arr, pivotIdx, right);
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pivotIdx = left;
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for (var i = left; i <= right - 1; i++) {
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if (compareFunc(pivotValue, arr[i]) >= 0) {
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swapElement(arr, i, pivotIdx);
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pivotIdx++;
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}
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}
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swapElement(arr, right, pivotIdx);
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if (pivotIdx === nth) {
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return pivotIdx;
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} else if (pivotIdx < nth) {
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left = pivotIdx + 1;
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} else {
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right = pivotIdx - 1;
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}
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}
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// Left == right
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return left;
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}
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function quickSelect(arr, left, right, nth, compareFunc) {
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if (arguments.length <= 3) {
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nth = left;
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if (arguments.length === 2) {
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compareFunc = defaultCompareFunc;
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} else {
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compareFunc = right;
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}
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left = 0;
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right = arr.length - 1;
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}
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return select(arr, left, right, nth, compareFunc);
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}
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export default quickSelect;
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