题解 | #二分查找-II#
二分查找-II
http://www.nowcoder.com/practice/4f470d1d3b734f8aaf2afb014185b395
package main
/**
* 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
*
* 如果目标值存在返回下标,否则返回 -1
* @param nums int整型一维数组
* @param target int整型
* @return int整型
*/
func search(nums []int, target int) int {
res := -1
if nums == nil || len(nums) == 0 {
return res
}
if nums[0] == target {
return 0
}
left := 0
right := len(nums) - 1
for left <= right {
mid := left + (right-left)>>1
if nums[mid] == target {
if nums[mid-1] != target {
return mid
} else {
right = mid - 1
}
} else if target < nums[mid] {
right = mid - 1
} else {
left = mid + 1
}
}
return res
}