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rotate.go
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rotate.go
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package rotate
func Search(nums []int, target int) bool {
n := len(nums)
if n < 1 {
return false
}
minIdx := 0
if nums[0] >= nums[n-1] {
for i := 0; i < n-1; i++ {
if nums[i] > nums[i+1] {
minIdx = i + 1
}
}
}
var ret bool
if target > nums[0] && minIdx > 0 {
ret = helper(nums, 0, minIdx-1, target)
} else if target == nums[0] {
return true
} else {
ret = helper(nums, minIdx, n-1, target)
}
return ret
}
func helper(nums []int, low, high, target int) bool {
for low < high {
mid := low + (high-low)/2
if nums[mid] < target {
low = mid + 1
} else {
high = mid
}
}
if nums[low] == target {
return true
}
return false
}
func Search2(nums []int, target int) bool {
n := len(nums)
if n < 1 {
return false
}
low, high := 0, n-1
for low < high {
mid := low + (high-low)/2
if nums[mid] == target {
return true
}
if nums[mid] > nums[high] {
if nums[mid] > target && nums[low] <= target {
high = mid
} else {
low = mid + 1
}
} else if nums[mid] < nums[high] {
if nums[mid] < target && nums[high] >= target {
low = mid + 1
} else {
high = mid
}
} else {
// nums[mid] == nums[high]
// ignore the duplicates
high--
}
}
if nums[low] == target {
return true
}
return false
}
func Search3(nums []int, target int) bool {
n := len(nums)
if n < 1 {
return false
}
low, high := 0, n-1
for low <= high {
mid := low + (high-low)/2
if nums[mid] == target {
return true
}
if nums[mid] > nums[high] {
if nums[mid] > target && nums[low] <= target {
high = mid - 1
} else {
low = mid + 1
}
} else if nums[mid] < nums[high] {
if nums[mid] < target && nums[high] >= target {
low = mid + 1
} else {
high = mid - 1
}
} else {
// nums[mid] == nums[high]
// ignore the duplicates
high--
}
}
return false
}