Triangle
Determine whether a triangle can be built from a given set of edges.
An array A consisting of N integers is given. A triplet (P, Q, R) is triangular if 0 ≤ P < Q < R < N and:
A[P] + A[Q] > A[R], A[Q] + A[R] > A[P], A[R] + A[P] > A[Q]. For example, consider array A such that:
A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 20 Triplet (0, 2, 4) is triangular.
Write a function:
func Solution(A []int) int
that, given an array A consisting of N integers, returns 1 if there exists a triangular triplet for this array and returns 0 otherwise.
For example, given array A such that:
A[0] = 10 A[1] = 2 A[2] = 5 A[3] = 1 A[4] = 8 A[5] = 20 the function should return 1, as explained above. Given array A such that:
A[0] = 10 A[1] = 50 A[2] = 5 A[3] = 1 the function should return 0.
Write an efficient algorithm for the following assumptions:
N is an integer within the range [0..100,000]; each element of array A is an integer within the range [−2,147,483,648..2,147,483,647].
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題目大意
如果該array存在一個三角形的三元組,則返回1, 否則返回0
解題思路
從大到小排序, 如果前面的值小於後面兩數和, 則可以組成三角形. 三數皆不能為0或負數
來源
https://app.codility.com/programmers/lessons/6-sorting/triangle/
解答
package Triangle
import "sort"
func Solution(A []int) int {
if len(A) < 3 {
return 0
}
sort.Ints(A)
for i := 0; i < len(A)-2; i++ {
if A[i+2] < A[i+1]+A[i] {
return 1
}
}
return 0
}