题目描述
给定一个数组，找出其中最小的K个数。例如数组元素是4,5,1,6,2,7,3,8这8个数字，则最小的4个数字是1,2,3,4。如果K>数组的长度，那么返回一个空的数组
示例1
输入
[4,5,1,6,2,7,3,8],4
返回值
[1,2,3,4]
方法一:
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| class Solution {
public:
vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
vector<int> result;
if(input.empty()||k>input.size())
return result;
ListNode *node = new ListNode(input[0]);
node->next = NULL;
ListNode *lastNode = NULL;
ListNode *head = node;
//插入排除
for(int i=1;i<input.size();i++)
{
while(node)
{
ListNode *newNode = new ListNode(input[i]);
if(input[i]>node->val)
{
lastNode = node;
node = node->next;
if(node==NULL)
{
//表尾处理
newNode->next = lastNode->next;
lastNode->next = newNode;
}
}
else
{
if(lastNode)
{
//中间处理
newNode->next = lastNode->next;
lastNode->next = newNode;
}else
{
//表头处理
newNode->next = node;
node = newNode;
head = node;
}
break;
}
}
node = head;
lastNode = NULL;
}
for(int i= 0;i<k;i++)
{
result.push_back(node->val);
node = node->next;
}
return result;
}
};
|
方法二:
class Solution {
public:
vector<int> GetLeastNumbers_Solution(vector<int> input, int k) {
vector<int> result;
if(input.empty()||k>input.size())
return result;
sort(input.begin(),input.end());
result.insert(result.begin(),input.begin(), input.begin()+k);
return result;
}
};