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node_modules/echarts/lib/util/quickSelect.js 2.78 KB
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  /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
  
  
  /**
   * AUTO-GENERATED FILE. DO NOT MODIFY.
   */
  
  /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
  function defaultCompareFunc(a, b) {
    return a - b;
  }
  function swapElement(arr, idx0, idx1) {
    var tmp = arr[idx0];
    arr[idx0] = arr[idx1];
    arr[idx1] = tmp;
  }
  function select(arr, left, right, nth, compareFunc) {
    var pivotIdx = left;
    var pivotValue;
    while (right > left) {
      pivotIdx = Math.round((right + left) / 2);
      pivotValue = arr[pivotIdx];
      // Swap pivot to the end
      swapElement(arr, pivotIdx, right);
      pivotIdx = left;
      for (var i = left; i <= right - 1; i++) {
        if (compareFunc(pivotValue, arr[i]) >= 0) {
          swapElement(arr, i, pivotIdx);
          pivotIdx++;
        }
      }
      swapElement(arr, right, pivotIdx);
      if (pivotIdx === nth) {
        return pivotIdx;
      } else if (pivotIdx < nth) {
        left = pivotIdx + 1;
      } else {
        right = pivotIdx - 1;
      }
    }
    // Left == right
    return left;
  }
  function quickSelect(arr, left, right, nth, compareFunc) {
    if (arguments.length <= 3) {
      nth = left;
      if (arguments.length === 2) {
        compareFunc = defaultCompareFunc;
      } else {
        compareFunc = right;
      }
      left = 0;
      right = arr.length - 1;
    }
    return select(arr, left, right, nth, compareFunc);
  }
  export default quickSelect;