Question 42306 in PHP Question posted in
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How to calculate the sum of every possible combinations of the Integer array? – PHP

Given an array of positive integers a, I want to calculate the sum of every possible a[i] ∘ a[j], where a[i] ∘ a[j] is the concatenation of the string representations of a[i] and a[j] respectively.

Example

For a = [10, 2], the output should be solution(a) = 1344.

a[0] ∘ a[0] = 10 ∘ 10 = 1010,
a[0] ∘ a[1] = 10 ∘ 2 = 102,
a[1] ∘ a[0] = 2 ∘ 10 = 210,
a[1] ∘ a[1] = 2 ∘ 2 = 22.
So the sum is equal to 1010 + 102 + 210 + 22 = 1344.

For a = [8], the output should be solution(a) = 88.

For a = [1, 2, 3], the output should be solution(a) = 198.

a[0] ∘ a[0] = 1 ∘ 1 = 11,
a[0] ∘ a[1] = 1 ∘ 2 = 12,
a[0] ∘ a[2] = 1 ∘ 3 = 13,
a[1] ∘ a[0] = 2 ∘ 1 = 21,
a[1] ∘ a[1] = 2 ∘ 2 = 22,
a[1] ∘ a[2] = 2 ∘ 3 = 23,
a[2] ∘ a[0] = 3 ∘ 1 = 31,
a[2] ∘ a[1] = 3 ∘ 2 = 32,
a[2] ∘ a[2] = 3 ∘ 3 = 33.
The total result is 11 + 12 + 13 + 21 + 22 + 23 + 31 + 32 + 33 = 198.
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2

Answers


  1. 0

    The above task can be solved using the following PHP code:

    Notes: $a = Integer array, $result = Integer

    function solution($a) {
    $result = 0;
    for($i=0;$i<count($a);$i++) {
        for($j=0;$j<count($a);$j++) {
            $result += (int)$a[$i].$a[$j];
        }
    }
    return $result;
}

    Try my above solution.

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  2. 0

    Python Solution for this problem:

    def solution(a):
    lowSum = 0
    cnt = 0
    for i in range(len(a)):
        lowSum += a[i];

    cnt += lowSum * len(a)

    for j in range(len(a)): 
        size = len(str(a[j]))
        offset = iPower(10, size)
        cnt = cnt + lowSum * offset

    return cnt

def iPower(base, power):
    result = 1
    for i in range(1,power+1):
        result *= base
    return result
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