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solution.js
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solution.js
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/**
* @param {number[]} nums
* @param {number} a
* @param {number} b
* @param {number} c
* @return {number[]}
*/
var sortTransformedArray = function (nums, a, b, c) {
if (nums.length < 2) {
return nums.map(item => a * item * item + b * item + c);
}
if (a !== 0) {
// 真 二次函数
const center = -b / (2 * a);
// index 数组中距离center最近的元素的索引
let index = 0;
let diff = Math.abs(nums[0] - center);
let low = 0;
let high = nums.length - 1;
while (low <= high) {
const mid = (low + high) >> 1;
const delta = Math.abs(nums[mid] - center);
if (delta < diff) {
index = mid;
diff = delta;
}
if (nums[mid] > center) {
high = mid - 1;
} else {
low = mid + 1;
}
}
let left, right;
if (index + 1 < right) {
left = index;
right = index + 1;
} else {
left = index - 1;
right = index;
}
let delta = 1;
let startIndex = 0;
if (a < 0) {
delta = -1;
startIndex = nums.length - 1;
}
const result = new Array(nums.length);
while (left > -1 && right < nums.length) {
const deltaL = Math.abs(nums[left] - center);
const deltaR = Math.abs(nums[right] - center);
if (deltaL < deltaR) {
result[startIndex] = a * nums[left] * nums[left] + b * nums[left] + c;
left--;
} else {
result[startIndex] = a * nums[right] * nums[right] + b * nums[right] + c;
right++;
}
startIndex += delta;
}
while (left > -1) {
result[startIndex] = a * nums[left] * nums[left] + b * nums[left] + c;
startIndex += delta;
left--;
}
while (right < nums.length) {
result[startIndex] = a * nums[right] * nums[right] + b * nums[right] + c;
startIndex += delta;
right++;
}
return result;
} else if (b !== 0) {
// 真一次函数
if (b > 0) {
return nums.map(item => b * item + c);
} else {
return nums.reverse().map(item => b * item + c);
}
} else {
// 常数
return new Array(nums.length).fill(c);
}
};