多种数组排序方法-蒲公英云

多种数组排序方法

1.随机生成数据

var a = (function (){ 
    var a = [];
    function randomInt(from, to){ 
        return parseInt(Math.random() * (to - from + 1) + from);
    }
    for (var i = 0; i < 10000; i++){ 
        a.push(randomInt(0, 1000000))
    }
    return a;
})();

2.插入排序

function insertionSort(){ 
    var date = new Date();
    for (var i = 1; i < a.length; i++){ 
        var temp = a[i];
        for (var j = i - 1; j >= 0 && a[j] > temp; j--){ 
            a[j + 1] = a[j];
        }
        a[j + 1] = temp;
    }
    console.log("插入排序的时间：" + (new Date() - date));
}

3.希尔排序

function shellSort(){ 
    var date = Date.now();
    for (var gap = a.length >> 1; gap > 0; gap >>= 1){ 
        for (var i = gap; i < a.length; i++){ 
            var temp = a[i];
            for (var j = i - gap; j >= 0 && a[j] > temp; j -= gap){ 
                a[j + gap] = a[j];
                // console.log(a[j])
            }
            a[j + gap] = temp;
            console.log(a[i],a[j])
            console.log(a)
        }
    }
    console.log("希尔排序的时间：" + (new Date() - date));
}

4.归并

function merge(a, b, lo, mid, hi){ 
    //每次归并前，都需要先把a中的数据copy到b中。
    for (var i = 0; i < a.length; i++){ 
        b[i] = a[i];
    }
    var i = lo, j = mid + 1;
    for (var k = lo; k <= hi; k++){ 
        if (i > mid){ 
            a[k] = b[j++];
        }else if (j > hi){ 
            a[k] = b[i++];
        }else if (b[i] < b[j]){ 
            a[k] = b[i++];
        }else{ 
            a[k] = b[j++]
        }
    }
}

5.归并排序

function sort(a, temp, lo, hi){ 
    if (lo >= hi) return;
    var mid = (hi + lo) >> 1;
    sort(a, temp, lo, mid);  //左半部分排序
    sort(a, temp, mid + 1, hi);//右半部分排序
    merge(a, temp, lo, mid, hi);
}

6. 快速排序

function quickSort(a, lo, hi){ 
    if (lo >= hi) return;
    var j = quickPartition(a, lo, hi);
    quickSort(a, lo, j - 1);
    quickSort(a, j + 1, hi);
}

7.快速排序的切分

function quickPartition(a, lo, hi){ 
    var i = lo, j = hi + 1;  //左右扫描指针
    var p = a[lo];  //切分元素
    for (; ;){ 
        //扫描左右,检查扫描是否结束，并交换元素
        while (a[++i] <= p){ 
            if (i == hi) break;
        }
        while (a[--j] >= p){ 
            if (j == lo) break;
        }
        //如果左指针超过了右指针则结束
        if (i >= j) break;
        //交换左右的元素
        exch(a, i, j);
    }
    //把a[lo]添加到指定的位置
    exch(a, lo, j);
    return j;
}
function exch(a, m, n){ 
    var temp = a[m];
    a[m] = a[n];
    a[n] = temp;
}