2019-05-28 12:49:05 +00:00
|
|
|
|
|
|
|
|
|
function swap(arr, index1, index2) {
|
|
|
|
|
var temp = arr[index1];
|
|
|
|
|
arr[index1] = arr[index2];
|
|
|
|
|
arr[index2] = temp;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
function bubbleSort(arr) {
|
|
|
|
|
for (var i = 0, len = arr.length; i < len; i++) {
|
|
|
|
|
// 改进: j < len - 1 - i,已经排好序的可以不用再比较
|
|
|
|
|
for(var j = 0; j < len - 1 - i; j++) {
|
|
|
|
|
if (arr[j] > arr[j+1]) {
|
|
|
|
|
swap(arr, j, j+1);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
var arr = [5,4,3,2,1];
|
|
|
|
|
// bubbleSort(arr);
|
|
|
|
|
|
|
|
|
|
function selectionSort(arr) {
|
|
|
|
|
var minIndex;
|
|
|
|
|
for (var i = 0; i < arr.length-1; i++) {
|
|
|
|
|
minIndex = i;
|
|
|
|
|
for (var j = i+1; j < arr.length; j++) {
|
|
|
|
|
if (arr[j] < arr[minIndex]) {
|
|
|
|
|
minIndex = j;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
swap(arr, minIndex, i);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
// selectionSort(arr);
|
|
|
|
|
|
|
|
|
|
function insertionSort(arr) {
|
|
|
|
|
if (arr.length < 2) return arr;
|
|
|
|
|
for (var i = 1, len = arr.length; i < len; i++) {
|
|
|
|
|
var j = i - 1;
|
|
|
|
|
var temp = arr[i]; // 相当于将i提取出,留个空位
|
|
|
|
|
while(j >=0 && arr[j] > temp) {
|
|
|
|
|
arr[j+1] = arr[j];
|
|
|
|
|
j--;
|
|
|
|
|
}
|
|
|
|
|
arr[j+1] = temp;
|
|
|
|
|
}
|
|
|
|
|
}
|
2019-05-29 12:37:28 +00:00
|
|
|
|
insertionSort(arr);
|
|
|
|
|
|
|
|
|
|
function mergeSort(arr) {
|
|
|
|
|
var len = arr.length;
|
|
|
|
|
if (len === 1) return arr;
|
|
|
|
|
var mid = Math.floor(len/2);
|
|
|
|
|
var left = arr.slice(0, mid);
|
|
|
|
|
var right = arr.slice(mid, len);
|
|
|
|
|
return merge(mergeSort(left), mergeSort(right));
|
|
|
|
|
}
|
|
|
|
|
function merge(left, right) {
|
|
|
|
|
var i = 0,
|
|
|
|
|
j = 0,
|
|
|
|
|
l = left.length,
|
|
|
|
|
r = right.length,
|
|
|
|
|
temp = [];
|
|
|
|
|
while(i < l && j < r) {
|
|
|
|
|
if (left[i] < right[j]) {
|
|
|
|
|
temp.push(left[i]);
|
|
|
|
|
i++;
|
|
|
|
|
} else {
|
|
|
|
|
temp.push(right[j]);
|
|
|
|
|
j++;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
if (i < l) {
|
|
|
|
|
temp.push(...left.slice(i));
|
|
|
|
|
}
|
|
|
|
|
if (j < r) {
|
|
|
|
|
temp.push(...right.slice(j));
|
|
|
|
|
}
|
|
|
|
|
return temp;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
function quickSort(arr, left, right) {
|
|
|
|
|
var index;
|
|
|
|
|
if (arr.length > 1) {
|
|
|
|
|
index = partition(arr, left, right);
|
|
|
|
|
if (left < index - 1) {
|
|
|
|
|
quickSort(arr, left, index-1);
|
|
|
|
|
}
|
|
|
|
|
if (right > index) {
|
|
|
|
|
quickSort(arr, index, right);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
function partition(arr, left, right) {
|
|
|
|
|
var pivot = arr[Math.floor((left+right)/2)],
|
|
|
|
|
i = left,
|
|
|
|
|
j = right;
|
|
|
|
|
while(i <= j) {
|
|
|
|
|
while(arr[i] < pivot) {
|
|
|
|
|
i++;
|
|
|
|
|
}
|
|
|
|
|
while(arr[j] > pivot) {
|
|
|
|
|
j--;
|
|
|
|
|
}
|
|
|
|
|
if (i <= j) {
|
|
|
|
|
swap(arr, i, j);
|
|
|
|
|
i++;
|
|
|
|
|
j--;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return i;
|
2019-05-30 11:54:19 +00:00
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
function binarySearch(arr, value) {
|
|
|
|
|
var left = 0,
|
|
|
|
|
right = arr.length - 1;
|
|
|
|
|
var mid;
|
|
|
|
|
while(left <= right) {
|
|
|
|
|
mid = Math.floor((left+right)/2);
|
|
|
|
|
if (value < arr[mid]) {
|
|
|
|
|
right = mid - 1;
|
|
|
|
|
} else if(value > arr[mid]){
|
|
|
|
|
left = mid + 1;
|
|
|
|
|
} else {
|
|
|
|
|
return mid;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return -1;
|
2019-05-29 12:37:28 +00:00
|
|
|
|
}
|