59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
package top100liked
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import (
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"fmt"
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"testing"
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)
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// https://leetcode.cn/problems/find-first-and-last-position-of-element-in-sorted-array/?envType=study-plan-v2&envId=top-100-liked
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func binarySearch(nums []int, target int) int {
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start := 0
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end := len(nums) - 1
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for start <= end {
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midIdx := start + (end-start)/2
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mid := nums[midIdx]
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if mid == target {
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return midIdx
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} else if mid > target {
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end = midIdx - 1
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} else if mid < target {
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start = midIdx + 1
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}
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}
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return -1
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}
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func searchRange(nums []int, target int) []int {
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res := binarySearch(nums, target)
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if res == -1 {
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return []int{-1, -1}
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}
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l, r := res-1, res+1
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for l >= 0 {
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_l := binarySearch(nums[:l+1], target)
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if _l == -1 {
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break
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} else {
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l = _l - 1
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}
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}
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for r < len(nums) {
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_r := binarySearch(nums[r:], target)
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if _r == -1 {
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break
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} else {
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r = r + _r + 1
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}
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}
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return []int{l + 1, r - 1}
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}
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func Test(t *testing.T) {
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nums := []int{5, 7, 7, 8, 8, 10}
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fmt.Printf("%+v\n", searchRange(nums, 8))
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fmt.Printf("%+v\n", searchRange(nums, 6))
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fmt.Printf("%+v\n", searchRange([]int{}, 0))
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}
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