/*
* source code from blog:
* http://www.acmerblog.com/leetcode-two-sum-5223.html
*
* 解法1：先排序，然后从开头和结尾同时向中间查找，原理也比较简单。复杂度O(nlogn)
*
* julia's comment:
*
*/
public static ArrayList twoSum(int[] numbers, int target)
{
int len = numbers.Length;
Node[] tmpNodes = new Node[len];
for (int i = 0; i < len; i++)
{
tmpNodes[i].id = i + 1;
tmpNodes[i].val = numbers[i];
}
Node[] nodes = sortArray(tmpNodes);
int start = 0, end = len - 1;
ArrayList ans = new ArrayList();
while (start < end)
{
if (nodes[start].val + nodes[end].val == target)
{
if (nodes[start].id > nodes[end].id)
{
swap(ref tmpNodes, start, end);
ans.Add(tmpNodes[start].id);
ans.Add(tmpNodes[end].id);
return ans;
}
else if (tmpNodes[start].val + tmpNodes[end].val < target)
start++;
else
end--;
}
}
return ans;
}
public static Node[] sortArray(Node[] nA)
{
return nA; // implement later
}
public static void swap(ref Node[] nA, int start, int end)
{
Node tmp = nA[start];
nA[start] = nA[end];
nA[end] = tmp;
}
public static bool compare(Node a, Node b)
{
return a.val < b.val;
}