Arrays 查找峰值元素(多个)SWIFT
如何在阵列中找到多个峰值 给定数组:[1,2,3,4,5,4,3,2,3,4,5,6,5,4,3,2,4,2] 我可以使用下面的代码找到最大峰值Arrays 查找峰值元素(多个)SWIFT,arrays,swift,search,element,Arrays,Swift,Search,Element,如何在阵列中找到多个峰值 给定数组:[1,2,3,4,5,4,3,2,3,4,5,6,5,4,3,2,4,2] 我可以使用下面的代码找到最大峰值 func findPeakElement(_ readings: [Int]) -> Int { if readings.count == 0 { return 0 } while left < right { middle1 = (left + right) / 2 middle2
func findPeakElement(_ readings: [Int]) -> Int {
if readings.count == 0 {
return 0
}
while left < right {
middle1 = (left + right) / 2
middle2 = middle1 + 1
if readings[middle1] < readings[middle2] {
left = middle2
} else {
right = middle1
}
}
return left
}
func findPeakElement(u读数:[Int])->Int{
如果读数.count==0{
返回0
}
而左<右{
中间1=(左+右)/2
中间2=中间1+1
如果读数[middle1]<读数[middle2]{
左=中2
}否则{
右=中1
}
}
左转
}
但是,;我需要找到所有的山峰;[5,6,4]
我需要什么代码?即使它只是告诉我峰值的数量(3),也足够了。假设您想要任何两边都有较低值的值,您可以执行以下操作:
func findPeaks(readings: [Int]) -> [Int] {
var result = [Int]()
if readings.count >= 3 {
for i in 1..<readings.count-1 {
if readings[i - 1] < readings[i] && readings[i + 1] < readings[i] {
result.append(readings[i])
}
}
}
return result
}
let readings = [1,2,3,4,5,4,3,2,3,4,5,6,5,4,3,2,4,2]
print(findPeaks(readings: readings))
此算法将找不到
4
。支持这一点需要更多的工作。您可以迭代元素,检查值是升序还是降序,并将元素与上一个元素进行比较。如果当前元素大于最后一个元素,则将其标记为升序。如果较小且为升序,则将其标记为降序并附加最后一个元素:
func findPeakElement(_ readings: [Int]) -> [Int] {
var ascending = false
var peaks: [Int] = []
if var last = readings.first {
readings.dropFirst().forEach {
if last < $0 {
ascending = true
}
if $0 < last && ascending {
ascending = false
peaks.append(last)
}
last = $0
}
}
return peaks
}
func findPeakElement(_ readings: [Int]) -> [Int] {
var ascending = false
var peaks: [Int] = []
if var last = readings.first {
readings.dropFirst().forEach {
if last < $0 {
ascending = true
}
if $0 < last && ascending {
ascending = false
peaks.append(last)
}
last = $0
}
}
return peaks
}
let readings = [1,2,3,4,5,4,3,2,3,4,5,6,5,4,3,2,4,2]
let peaks = findPeakElement(readings)
print(peaks) // [5, 6, 4]