You are to write a series of static functions to gain experience working with arrays.  Feel free to jump around as you wish but I want to see the first 6 completed.

Write a static method that, given an array of ints, returns true if the array is length 1 or more, and the first element and the last element are the same.

sameFirstLast({1, 2, 3}) → false
sameFirstLast({1, 2, 3, 1}) → true
sameFirstLast({1, 2, 1}) → true

Write a static method that, given an array of ints, swaps the first and last elements in the array. Return the modified array. The array length will be at least 1.

swapEnds({1, 2, 3, 4}) → {4, 2, 3, 1}
swapEnds({1, 2, 3}) → {3, 2, 1}
swapEnds({8, 6, 7, 9, 5}) → {5, 6, 7, 9, 8}

Write a static method that, given an array of ints, return the sum of all the elements.

sum({1, 2, 3}) → 6
sum({5, 11, 2, 3}) → 21
sum({7, 0, 0, 3, 5}) → 15

Write a static method that, given an array of ints, returns the index of the smallest value.

findSmallest({4, 5, 2, 1}) → 3
findSmallest({3, 6, 5}) → 0

Write a static method that, given a non-empty array of ints, return a new array containing the elements from the original array that come before the first 4 in the original array. The original array will contain at least one 4.

pre4({1, 2, 4, 1}) → {1, 2}
pre4({3, 1, 4}) → {3, 1}
pre4({1, 4, 4}) → {1}

Write a static method named stutter that accepts an array of integers as its parameter and returns a new array with two consecutive copies of each value from the original array. You may assume that the array passed is not null.

For example, if the following array is passed:

int[] a = {11, -4, 0, 777};
int[] stuttered = stutter(a);

After the call, the array stuttered should store the elements {11, 11, -4, -4, 0, 0, 777, 777}.

Impress me

1) Say that a “clump” in an array is a series of 2 or more adjacent elements of the same value. Return the number of clumps in the given array.

countClumps({1, 2, 2, 3, 4, 4}) → 2
countClumps({1, 1, 2, 1, 1}) → 2
countClumps({1, 1, 1, 1, 1}) → 1

2) Given a non-empty array, return true if there is a place to split the array so that the sum of the numbers on one side is equal to the sum of the numbers on the other side.

canBalance({1, 1, 1, 2, 1}) → true
canBalance({2, 1, 1, 2, 1}) → false
canBalance({10, 10}) → true

(3 votes, average: 2.33 out of 5)

 Loading ...