167. Two Sum II

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.

Note:

• Your returned answers (both index1 and index2) are not zero-based.
• You may assume that each input would have exactly one solution and you may not use the same element twice.

Example:

Input: numbers = [2,7,11,15], target = 9
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.

这道题刚做的时候不知道题目让我返回什么...大小为 returnSize 的数组，返回值是个指针,这个指针指向一个长度为 returnSize 的 int 数组。

/**
* Return an array of size *returnSize.
* Note: The returned array must be malloced, assume caller calls free().
*/
int* twoSum(int* numbers, int numbersSize, int target, int* returnSize) {
    int mid,low=0,high=numbersSize-1,sum;
    int *nums=(int*)malloc(sizeof(int)*2); 
    while(low<=high){
        sum=numbers[low]+numbers[high];
        if(sum==target){
            nums[0]=low+1;
            nums[1]=high+1;
            break;
        }    
        else if(sum<target)    low++;
        else high--;
    }
    *returnSize=2;
    return nums;
}