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Codility---MinAvgTwoSlice
A non-empty zero-indexed array A consisting of N integers is given. A pair of integers (P, Q), such that 0 ≤ P < Q < N, is called a slice of array A (notice that the slice contains at least two elements). The average of a slice (P, Q) is the sum of A[P] + A[P + 1] + ... + A[Q] divided by the length of the slice. To be precise, the average equals (A[P] + A[P + 1] + ... + A[Q]) / (Q − P + 1).
For example, array A such that:
A[0] = 4 A[1] = 2 A[2] = 2 A[3] = 5 A[4] = 1 A[5] = 5 A[6] = 8contains the following example slices:
- slice (1, 2), whose average is (2 + 2) / 2 = 2;
- slice (3, 4), whose average is (5 + 1) / 2 = 3;
- slice (1, 4), whose average is (2 + 2 + 5 + 1) / 4 = 2.5.
The goal is to find the starting position of a slice whose average is minimal.
Write a function:
class Solution { public int solution(int[] A); }
that, given a non-empty zero-indexed array A consisting of N integers, returns the starting position of the slice with the minimal average. If there is more than one slice with a minimal average, you should return the smallest starting position of such a slice.
For example, given array A such that:
A[0] = 4 A[1] = 2 A[2] = 2 A[3] = 5 A[4] = 1 A[5] = 5 A[6] = 8the function should return 1, as explained above.
Assume that:
- N is an integer within the range [2..100,000];
- each element of array A is an integer within the range [−10,000..10,000].
Complexity:
- expected worst-case time complexity is O(N);
- expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).
Elements of input arrays can be modified.
// you can also use imports, for example:// import java.util.*;// you can write to stdout for debugging purposes, e.g.// System.out.println("this is a debug message");class Solution { public int solution(int[] A) { // write your code in Java SE 8 int minAvgIdx=0; double minAvg = (A[0]+A[1])/2; double currAvg; for(int i=0; i< A.length-2; i++) { //two number currAvg = (double)(A[i] +A[i+1])/2; if(minAvg > currAvg) { minAvg = currAvg; minAvgIdx = i; } //three number currAvg =(double) (A[i] +A[i+1] +A[i+2])/3; if(minAvg > currAvg) { minAvg = currAvg; minAvgIdx = i; } } currAvg =(double) (A[A.length-2] +A[A.length-1])/2; if(minAvg > currAvg) { minAvg = currAvg; minAvgIdx = A.length-2; } return minAvgIdx; }}
https://codility.com/demo/results/trainingP69B3H-F2P/
Codility---MinAvgTwoSlice