import java.util.*; public class Solution { /** * 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 */ public int search (int[] nums, int target) { if(nums == null || nums.length == 0){ return -1; }
// write code here
int left = 0; int mid = 0; int right = nums.length - 1; int targetIndex = -1; while(left <= right){ mid = left + ((right - left) / 2); if(nums[left] == target){ targetIndex = left; break; } if(nums[right] == target){ targetIndex = right; break; } if(nums[mid] == target){ targetIndex = mid; break; } if(left + 1 == right || left == right){ break; } if(nums[mid] < target){ //目标在右侧 left = mid + 1; } else { //目标在左侧 right = mid; } } if(targetIndex != -1){ //找到了 但不一定是最左侧的 return findLeftIndex(nums,targetIndex,target); } else { return -1; } } public int findLeftIndex(int[] nums,int index,int target){ while(nums[index] == target){ if(index == 0){ return index; } index --; } return index + 1; } }