题解 | #二分查找-II#

/**
 * 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 numsLen int nums数组长度
 * @param target int整型 
 * @return int整型
 */

int findFirst(int* nums, int numsLen, int target){
    if(numsLen <1){
        return -1;
    } 
    int low =0;
    int high = numsLen-1;
    while(low <= high){
        int mid = (low + high)/2;
        if(target > nums[mid]){
            low = mid+1;
        }else if(target == nums[mid] && (mid -1 < 0 || nums[mid-1] != target)){
            return mid;
        }else{
            high = mid -1;
        }
    }
        return -1;





}


int search(int* nums, int numsLen, int target ) {
    // write code here
    if(numsLen == 0){
        return -1;
    }
    int result = 0;
    result = findFirst(nums,numsLen,target);
    return result;
}