Tech It Yourself
tháng 1 20, 2020
0
Let A be a non-empty array consisting of N integers.
The abs sum of two for a pair of indices (P, Q) is the absolute value |A[P] + A[Q]|, for 0 ≤ P ≤ Q < N.
For example, the following array A:
A[0] = 1
A[1] = 4
A[2] = -3
has pairs of indices (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2).
The abs sum of two for the pair (0, 0) is A[0] + A[0] = |1 + 1| = 2.
The abs sum of two for the pair (0, 1) is A[0] + A[1] = |1 + 4| = 5.
The abs sum of two for the pair (0, 2) is A[0] + A[2] = |1 + (−3)| = 2.
The abs sum of two for the pair (1, 1) is A[1] + A[1] = |4 + 4| = 8.
The abs sum of two for the pair (1, 2) is A[1] + A[2] = |4 + (−3)| = 1.
The abs sum of two for the pair (2, 2) is A[2] + A[2] = |(−3) + (−3)| = 6.
Write a function:
int solution(vector<int> &A);
that, given a non-empty array A consisting of N integers, returns the minimal abs sum of two for any pair of indices in this array.
For example, given the following array A:
A[0] = 1
A[1] = 4
A[2] = -3
the function should return 1, as explained above.
Given array A:
A[0] = -8
A[1] = 4
A[2] = 5
A[3] =-10
A[4] = 3
the function should return |(−8) + 5| = 3.
Write an efficient algorithm for the following assumptions:
N is an integer within the range [1..100,000];
each element of array A is an integer within the range [−1,000,000,000..1,000,000,000].
The abs sum of two for a pair of indices (P, Q) is the absolute value |A[P] + A[Q]|, for 0 ≤ P ≤ Q < N.
For example, the following array A:
A[0] = 1
A[1] = 4
A[2] = -3
has pairs of indices (0, 0), (0, 1), (0, 2), (1, 1), (1, 2), (2, 2).
The abs sum of two for the pair (0, 0) is A[0] + A[0] = |1 + 1| = 2.
The abs sum of two for the pair (0, 1) is A[0] + A[1] = |1 + 4| = 5.
The abs sum of two for the pair (0, 2) is A[0] + A[2] = |1 + (−3)| = 2.
The abs sum of two for the pair (1, 1) is A[1] + A[1] = |4 + 4| = 8.
The abs sum of two for the pair (1, 2) is A[1] + A[2] = |4 + (−3)| = 1.
The abs sum of two for the pair (2, 2) is A[2] + A[2] = |(−3) + (−3)| = 6.
Write a function:
int solution(vector<int> &A);
that, given a non-empty array A consisting of N integers, returns the minimal abs sum of two for any pair of indices in this array.
For example, given the following array A:
A[0] = 1
A[1] = 4
A[2] = -3
the function should return 1, as explained above.
Given array A:
A[0] = -8
A[1] = 4
A[2] = 5
A[3] =-10
A[4] = 3
the function should return |(−8) + 5| = 3.
Write an efficient algorithm for the following assumptions:
N is an integer within the range [1..100,000];
each element of array A is an integer within the range [−1,000,000,000..1,000,000,000].
#include <algorithm> int solution(vector<int> &A) { // write your code in C++11 (g++ 4.8.2) if (A.size() == 1) return abs(A[0]) * 2; sort(A.begin(), A.end(), [](int a, int b) { return abs(a) < abs(b); }); int min_sum = abs(A[0]) * 2; for (int i = 0; i < A.size() - 1; i++) { min_sum = min(min_sum, abs(A[i] + A[i + 1])); } return min_sum; }
