JS數據結構與算法（三）

JS數據結構與算法（三）

一些排序算法，未完待續

function Sort() {

    swap = function (arr, a, b) {
        var tmp = arr[a];
        arr[a] = arr[b];
        arr[b] = tmp;
    };

    this.bubbleSort = function (arr) {

            var len,
            i,
            j;

        for (i = 0, len = arr.length; i < len; i++) {
            for (j = 0; j < len - 1 - i; j++) {
                if (arr[j] > arr[j + 1]) {
                    swap(arr, j, j + 1);
                }
            }
        }

        return arr;
    };

    this.selectSort = function (arr) {

        var len,
            indexMin,
            i,
            j,
            minValue;

        for (i = 0, len = arr.length; i < len; i++) {
            indexMin = i;

            for (j = i; j < len; j++) {
                if (arr[j] < arr[indexMin]) {
                    indexMin = j;
                }
            }

            if (indexMin !== i) {
                swap(arr, i, indexMin);
            }
        }   

        return arr;
    };

    this.insertSort = function (arr) {

        var i,
            j,
            len,
            tmp;
            flag = false;

        for (i = 1, len = arr.length; i < len; i++) {
            j = i;
            tmp = arr[i];

            while (j > 0 && arr[j - 1] > tmp) {
                arr[j] = arr[j - 1];
                j--;
            } 

            arr[j] = tmp;
        }

        return arr;
    };

    var merge = function (leftArr, rightArr) {
        var res = [],
            i = 0,
            j = 0,
            lenLeft = leftArr.length,
            lenRight = rightArr.length;

        while (i < lenLeft && j < lenRight) {
            if (leftArr[i] < rightArr[j]) {
                res.push(leftArr[i++]);
            } else {
                res.push(rightArr[j++]);
            }
        }   

        while (i < lenLeft) {
            res.push(leftArr[i++]);
        }
        while (j < lenRight) {
            res.push(rightArr[j++]);
        }

        return res;
    };

    var mergeSortRec = function(arr) {

        var len = arr.length,
            mid,
            l,
            r;

        if (len === 1) {
            return arr;
        } else {
            mid = len >> 1;
            l = arr.slice(0, mid);
            r = arr.slice(mid, len);
            return merge(mergeSortRec(l), mergeSortRec(r));
        }
    };

    this.mergeSort = function (arr) {

        arr = mergeSortRec(arr);    
        return arr;
    };

    var partition = function (arr, lef, rig) {

        var pi = arr[(lef + rig) >> 1],
            i = lef,
            j = rig;

        while (i <= j) {
            while (arr[i] < pi) {
                i++;
            }
            while (arr[j] > pi) {
                j--;
            }

            if (i <= j) {
                swap(arr, i, j);
                i++;
                j--;
            }
        }

        return i;
    };

    var quick = function (arr, lef, rig) {

        var index,
            len = arr.length;

        if (len > 1) {

            index = partition(arr, lef, rig);

            if (lef < index - 1) {
                quick(arr, lef, index - 1);
            }
            if (rig > index) {
                quick(arr, index, rig);
            }
        }   

        return arr;
    };

    this.quickSort = function (arr) {

        arr = quick(arr, 0, arr.length - 1);
        return arr; 
    };

    this.shellSort = function (arr) {

        var len = arr.length,
            i,
            j,
            gap;

        for (gap = len >> 1; gap > 0; gap >>= 1) {
            for (i = gap; i < len; i++) {
                for (j = i - 1; j >= 0 && arr[j] > arr[j + gap]; j -= gap) {
                    swap(arr, j, j + gap);
                }
            }
        }

        return arr;
    };
}

var arr = [-1, 7, -5, 9, 3, 4, 6, 8, 4];
var mySort = new Sort();
// arr = mySort.bubbleSort(arr);
// arr = mySort.selectSort(arr);
// arr = mySort.insertSort(arr);
// arr = mySort.mergeSort(arr); 
// arr = mySort.quickSort(arr);
// arr = mySort.shellSort(arr);
console.log(arr);