java - 将所有非零整数移至数组的开头

Question

我试图将所有非零整数移动到数组“a”的开头/左侧(例如 {0,0,4,3,0} 变为 {4,3,0,0 ,0})

这是我的程序。它编译并运行没有错误，但数组最终只有零。如有任何建议，我们将不胜感激。

int[] squeezeLeft(int[] a) {
    int count = 0;
    //creates new array
    int [] a2 = new int[a.length];
    //loops through a
    for (int i = 0; i< a.length; i++){
        //gets a temporary value from a[i]
        int temp = a[i];
        //assigns a[i] to temporary variable
        a[count] = temp;
        a[i] = 0;
                  /* raises count integer by one, so the following indice which is zero, is replaced

                  by  the following non=zero integer*/
        count++;
    }
    return a2;
}

Answer 1

我知道这不是非常有效的解决方案O^2，但它会满足您的要求。

private static int[] sequeezeLeft(final int[] a) {
    for (int i = 0; i < a.length; i++) {
        if (a[i] != 0) {
            for (int j = 0; j < a.length; j++) {
                if (a[j] == 0) {
                    a[j] = a[i];
                    a[i] = 0;
                }
            }
        }
    }
    return a;
}

时间复杂度为 O(n) 的另一个版本

    private static int[] sqeeze2(int [] a){
    int index = 0;
    if(a.length == 0)
        return a;
    for(int i=0;i<a.length;i++){
        if(a[i] !=0 && index < a.length){
            a[index] = a[i];
            a[i]=0;
            index++;
        }
    }
    return a;
}