mirror of
https://github.com/linghuam/boutique-books.git
synced 2024-10-16 15:45:48 +00:00
113 lines
2.5 KiB
JavaScript
113 lines
2.5 KiB
JavaScript
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function swap(arr, index1, index2) {
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var temp = arr[index1];
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arr[index1] = arr[index2];
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arr[index2] = temp;
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}
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function bubbleSort(arr) {
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for (var i = 0, len = arr.length; i < len; i++) {
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// 改进: j < len - 1 - i,已经排好序的可以不用再比较
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for(var j = 0; j < len - 1 - i; j++) {
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if (arr[j] > arr[j+1]) {
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swap(arr, j, j+1);
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}
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}
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}
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}
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var arr = [5,4,3,2,1];
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// bubbleSort(arr);
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function selectionSort(arr) {
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var minIndex;
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for (var i = 0; i < arr.length-1; i++) {
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minIndex = i;
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for (var j = i+1; j < arr.length; j++) {
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if (arr[j] < arr[minIndex]) {
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minIndex = j;
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}
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}
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swap(arr, minIndex, i);
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}
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}
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// selectionSort(arr);
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function insertionSort(arr) {
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if (arr.length < 2) return arr;
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for (var i = 1, len = arr.length; i < len; i++) {
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var j = i - 1;
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var temp = arr[i]; // 相当于将i提取出,留个空位
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while(j >=0 && arr[j] > temp) {
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arr[j+1] = arr[j];
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j--;
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}
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arr[j+1] = temp;
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}
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}
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insertionSort(arr);
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function mergeSort(arr) {
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var len = arr.length;
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if (len === 1) return arr;
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var mid = Math.floor(len/2);
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var left = arr.slice(0, mid);
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var right = arr.slice(mid, len);
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return merge(mergeSort(left), mergeSort(right));
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}
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function merge(left, right) {
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var i = 0,
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j = 0,
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l = left.length,
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r = right.length,
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temp = [];
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while(i < l && j < r) {
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if (left[i] < right[j]) {
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temp.push(left[i]);
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i++;
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} else {
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temp.push(right[j]);
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j++;
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}
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}
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if (i < l) {
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temp.push(...left.slice(i));
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}
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if (j < r) {
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temp.push(...right.slice(j));
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}
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return temp;
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}
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function quickSort(arr, left, right) {
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var index;
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if (arr.length > 1) {
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index = partition(arr, left, right);
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if (left < index - 1) {
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quickSort(arr, left, index-1);
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}
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if (right > index) {
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quickSort(arr, index, right);
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}
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}
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}
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function partition(arr, left, right) {
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var pivot = arr[Math.floor((left+right)/2)],
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i = left,
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j = right;
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while(i <= j) {
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while(arr[i] < pivot) {
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i++;
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}
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while(arr[j] > pivot) {
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j--;
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}
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if (i <= j) {
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swap(arr, i, j);
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i++;
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j--;
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}
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}
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return i;
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} |