LeetCode 1. Two Sum

Given an array of integers, 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. Please note that your returned answers (both index1 and index2) are not zero-based.

You may assume that each input would have exactly one solution.

Input: numbers={2, 7, 11, 15}, target=9
Output: index1=1, index2=2

foreach ($input as $key => $value)
{
    if (in_array($target - $value, $input))
        //...
}

class tuple
{
public:
    int first;
    int second;
}

unordered_map<int, tuple> m;

typedef struct
{
    int index_;
    int value_;
} input_element;

int compare(const void * a, const void * b)
{
    return ((input_element*)a)->value_ - ((input_element*)b)->value_;
}

void swap(int *a, int *b)
{
    int t = *a;
    *a = *b;
    *b = t;
}

int* twoSum(int* nums, int numsSize, int target)
{
    int *ret = (int*)malloc(2 * sizeof(int));
    input_element * inputs = (input_element *)malloc(numsSize * sizeof(input_element));
    for (int i = 0; i < numsSize; ++i)
    {
        inputs[i].index_ = i + 1;
        inputs[i].value_ = nums[i];
    }
    qsort(inputs, numsSize, sizeof(input_element), compare);
    int left = 0;
    int right = numsSize - 1;
    do
    {
        int sum = inputs[left].value_ + inputs[right].value_;
        if (sum < target)
        {
            ++left;
        }
        else if (sum > target)
        {
            --right;
        }
        else
        {
            break;
        }
    } while (1); //题目已经指出这个解肯定存在
    ret[0] = inputs[left].index_;
    ret[1] = inputs[right].index_;
    if (ret[0] > ret[1])
    {
        swap(ret, ret + 1);
    }
    return ret;
}