有序数组取中值详解编程语言

private static double findMidNumber(int arr1[], int arr2[]) { 
    int len1 = arr1.length; 
    int len2 = arr2.length; 
    int arr3[] = new int[len1 + len2]; 
    int i = 0,j = 0, k = 0; 
    while (i < len1 && j < len2) { 
        if (arr1[i] <= arr2[j]) { 
            arr3[k++] = arr1[i]; 
            i++; 
        } else { 
            arr3[k++] = arr2[j]; 
            j++; 
        } 
    } 
    while (i < len1) { 
        arr3[k++] = arr1[i++]; 
    } 
 
    while (j < len2) { 
        arr3[k++] = arr2[j++]; 
    } 
 
    System.out.println("find + " + k); 
    if (arr3.length % 2 == 0) { 
        return (arr3[(len1 + len2) / 2 - 1] + arr3[(len1 + len2) / 2]) / 2.0; 
    } else { 
        return arr3[(len1 + len2) / 2] * 1.0; 
    } 
}

private static double findMidNumber1(int arr1[], int arr2[]) { 
        int len1 = arr1.length; 
        int len2 = arr2.length; 
 
        int arr3[] = new int[(len1 + len2) / 2 +1]; 
 
        int i = 0,j = 0, k = 0, index = 0; 
        while (index < arr3.length && j < len2 && i < len1) { 
            if (arr1[i] <= arr2[j]) { 
                arr3[index++] =arr1[i]; 
                i ++; 
            } else { 
                arr3[index++] =arr2[j]; 
                j++; 
            } 
            k ++; 
        } 
        while (index < arr3.length) { 
            if ( i < len1) { 
                arr3[index++] =arr1[i++]; 
            } 
            if ( j < len2) { 
                arr3[index++] =arr2[j++]; 
            } 
            k ++; 
        } 
        System.out.println("find1 + " + k); 
        if (arr3.length % 2 == 1) { 
            return (arr3[arr3.length - 2] + arr3[arr3.length - 1] )/ 2.0; 
        } else { 
            return arr3[arr3.length - 1] * 1.0; 
        } 
 
    }

private static double findMidNumber3(int arr1[], int arr2[]) { 
        int len1 = arr1.length; 
        int len2 = arr2.length; 
 
        int l = (len1 + len2 + 1) / 2; 
        int r = (len1 + len2 + 2) / 2; 
 
        return (findMin(arr1, 0, arr2, 0, l) + findMin(arr1, 0, arr2, 0, r)) / 2.0; 
    } 
    private static int findMin(int arr1[], int l, int arr2[],int r, int k) { 
        if (l > arr1.length - 1) return arr2[r + k -1]; 
        if (r > arr2.length - 1) return arr1[l + k -1]; 
        if (k == 1) return Math.min(arr1[l], arr2[r]); 
 
        n++; 
        int min1 = Integer.MIN_VALUE, min2 = Integer.MIN_VALUE; 
 
        if (l + k/2 -1 < arr1.length) { 
            min1 = arr1[l + k/2 -1]; 
        } 
        if (r + k/2 -1 < arr2.length) { 
            min2 = arr2[r + k/2 -1]; 
        } 
        return  (min1 < min2) ? findMin(arr1, l + k/2, arr2, r, k - k/2) : 
            findMin(arr1, l, arr2, r + k/2, k - k/2); 
    }