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This time I will bring you the simplest search, sorting, and deduplication algorithm implemented in JS. What are the things to pay attention to in JS implementation of search, sorting, and deduplication? The following is a practical case. Let’s take a look. one time. Today I summarized a simple sorting algorithm
[Custom sorting]
First find the smallest number, and then compare this number with other numbers in the array. If you find a number smaller than this number, swap the two numbers, and then continue to find the next smallest number for the next round of comparison
var arr = [31, 6, 19, 8, 2, 3];
function findMin(start, arr) {
var iMin = arr[start];
var iMinIndex = start;
for (var i = start + 1; i < arr.length; i++) {
if (arr[i] < iMin) {
iMin = arr[i];
iMinIndex = i;
}
}
return iMinIndex;
}
function sort1(arr) {
for (var i = 0; i < arr.length; i++) {
var iMinIndex = findMin(i, arr);
var car;
car = arr[i];
arr[i] = arr[iMinIndex];
arr[iMinIndex] = car;
}
return arr;
}
document.write(sort1(arr));[Linear Search]: Search one by one
//不重复 有序
var arr = [0];
for (var i = 1; i < 100000; i++) {
arr[i] = arr[i - 1] + Math.floor(Math.random() * 4 + 1);
}
function find1(n, arr) {
for (var i = 0; i < arr.length; i++) {
if (arr[i] == n) {
return true;
}
}
return false;
}
//测试性能
var t1 = new Date().getTime();
for (var i = 0; i < 10000; i++) {
var n = Math.random() * 10000;
find2(n, 0, arr.length - 1)
}
alert(new Date().getTime() - t1);【
Binary search】: Keep dividing it into two parts. Partial search is a universal method, not necessarily the best, but a guaranteed method. . (Divide and conquer method)
***Add the middle values and divide by two, uniformly left, round down
//不重复 有序
var arr = [12, 17, 23, 34, 45, 76, 89];
function find2(n, s, e) {
//边界处理
if (s > e) {
return false;
} else if (s == e) {
if (arr[s] == n) {
return true;
} else {
return false;
}
}
var c = Math.floor((s + e) / 2);
if (arr[c] == n) {
return true;
} else {
if (n < arr[c]) {
return find2(n, s, c);
} else {
return find2(n, c + 1, e);
}
}
}
alert(find2(34, 0, arr.length - 1)); //true false[Boundary processing]-----Recursion, one level Find one layer down
//要求数组不重复有顺序\
var arr = [12, 23, 34, 45, 56, 67, 78]
function find2(n, s, e) {
if (s > e) {
return fasle;
} else if (s == e) {
if (arr[s] == e) {
return true;
} else {
return false;
}
}
var c = Math.floor((s + e) / 2);
if (arr[c] == n) {
return true;
} else {
if (n < arr[c]) {
return find2(n, s, c);
} else {
return find2(n, c + 1, e);
}
}
}
alert(find2(12, arr.length + 1, 78));Application
【Find minimum value】
var arr = [12, 54, 32, 9, 5, 3, 1, 101, -100, -1000];
function findMin(s, e) {
if (s > e) {
return [];
} else if (s == e) {
return arr[s];
} else if (s == e - 1) {
if (arr[s] < arr[e]) {
return arr[s];
} else {
return arr[e];
}
}
var c = Math.floor((s + e) / 2);
var l = findMin(s, c);
var r = findMin(c + 1, e);
if (l < r) {
return l;
} else {
return r;
}
}
alert(findMin(0, arr.length - 1));【Array deduplication】
var arr = [1, 2, 3, 4, 5, 4, 3, 4, 5, 2, 1, 4, 2, 1, 5, 7];
function findInArr(n, arr) {
for (var i = 0; i < arr.length; i++) {
if (arr[i] == n) {
return true;
}
}
return false;
}
function removeCopy(s, e) {
if (s > e) {
return [];
} else if (s == e) {
return [arr[s]];
} else if (s == e - 1) {
if (arr[s] == arr[e]) {
return [arr[s]];
} else {
return [arr[s], arr[e]]
}
}
var c = Math.floor((s + e) / 2);
var l = removeCopy(s, c);
var r = removeCopy(c + 1, e);
for (var i = 0; i < r.length; i++) {
if (!findInArr(r[i], l)) {
l.push(r[i]);
}
}
return l;
}
document.write(removeCopy(0, arr.length - 1));【
Array sortingBubble sortBubbleSortLoop, take out two values each time and compare them two by two. If the next value is smaller than the current one, then Swap positions
The outer loop is to loop to get the numbers, and the inner loop is to swap the numbers in pairs
var arr = [ - 122, -2, 5, 6, 73, 34, 5, 2];
function BubbleSort(arr) {
for (var i = 0; i < arr.length; i++) {
for (var j = 0; j < arr.length - 1; j++) {
if (arr[j] > arr[j + 1]) {
var tmp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = tmp
}
}
}
return arr;
}
document.write(BubbleSort(arr));
[Quick Sort] -------quickSort
Get For the number in the middle of the array, place the number smaller than the middle number on the left side of the middle number, and the larger number than the middle number on the right side, and then link the two times together
function quickSort(arr, s, e) {
//边界处理 参与流程
if (arr.length == 0) {
return [];
}
var c = Math.floor((s + e) / 2);
var arrC = arr.splice(c, 1);
var l = [];
var r = [];
for (var i = 0; i < arr.length; i++) {
if (arr[i] < arrC) {
l.push(arr[i]);
} else {
r.push(arr[i]);
}
}
return quickSort(l).concat(arrC, quickSort(r));
}
var arr = [5, 5, 12, 56, 1, 67, -1, -23 - 1];
document.write(quickSort(arr, 0, arr.length - 1));
[Hash] hash Hash array ------ Commonly used structures in js
Add
var arr = [];
arr.length = 0;
var cont = 0;
function hash_add(n) {
var pos = n % arr.length;
//当空间不足的时候
if (arr[pos]) {
while (arr[pos]) {
cont++;
if (arr[pos] == n) {
return;
} else {
pos++;
if (pos == arr.length) {
pos = 0;
}
}
}
arr[pos] = n;
} else {
arr[pos] = n;
}
//空间不足的时候的扩建
if (cont == arr.length) {
//d等呗扩建
var oldArr = arr;
arr.length = oldArr.length * 2;
arr = [];
for (var i = 0; i < oldArr.length; i++) {
arr.push(oldArr[i]);
count = 0;
}
}
}
hash_add();
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!
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