滑动窗口的最大值

题目：给定一个数组和滑动窗口的大小，请找到所有滑动窗口里的最大值。例如，如果输入数组{2,3,4,2,6,2,5,1}及滑动窗口的大小3，那么一共存在6个滑动窗口，他们的最大值分别是{4,4,6,6,6,5}，如图所示：

 1 #include<iostream>
 2 #include<vector>
 3 #include<deque>
 4 using namespace std;
 5
 6 vector<int> maxInWindows(const vector<int>& num,unsigned int size)
 7 {
 8  vector<int> MaxInWindows;
 9  if(num.size()>size&&size>=1)
10  {
11   deque<int> index;
12   for(unsigned int i=0;i<size;++i)
13   {
14    while(!index.empty()&&num[i]>=num[index.back()])
15      index.pop_back();
16    index.push_back(i);
17    }
18   for(i=size;i<num.size();++i)
19   {
20     MaxInWindows.push_back(num[index.front()]);
21     while(!index.empty()&&num[i]>=num[index.back()])
22     index.pop_back();
23     if(!index.empty()&&index.front()<(int)(i-size))
24         index.pop_front();
25     index.push_back(i);
26   }
27  MaxInWindows.push_back(num[index.front()]);
28  }
29 return MaxInWindows;
30 }
31
32 void print(vector<int> result)
33 {
34     vector<int>::iterator ite;
35     for(ite=result.begin();ite!=result.end();++ite)
36         cout<<*ite<<" ";
37         cout<<endl;
38          result.clear();
39 }
40
41 void main()
42 {
43     int ia[10]={1,2,3,4,5,6,7,8,9,10};
44     vector<int> ib(ia,ia+10);
45     print(maxInWindows(ib,3));
46 }

方法2：

 1 #include<iostream>
 2 #include<vector>
 3 #include<deque>
 4 using namespace std;
 5
 6
 7 int searchmax(const vector<int>&num,unsigned int size)
 8 {
 9      int max=num[0];
10     for(int i=1;i<size;i++)
11     {
12         if(num[i]>max)
13             max=num[i];
14     }
15     return max;
16 }
17
18 vector<int> maxInWindows(vector<int>& num,unsigned int size)
19 {
20  vector<int> MaxInWindows;
21  int length=num.size();
22  for(int i=0;i<length-size+1;i++)
23  {
24   MaxInWindows.push_back(searchmax(num,size));
25       num.erase(num.begin());
26  }
27 return MaxInWindows;
28 }
29
30
31
32
33 void print(vector<int> result)
34 {
35     vector<int>::iterator ite;
36     for(ite=result.begin();ite!=result.end();++ite)
37         cout<<*ite<<" ";
38         cout<<endl;
39          result.clear();
40 }
41
42 void main()
43 {
44     int ia[10]={1,2,3,4,5,6,7,8,9,10};
45     vector<int> ib(ia,ia+10);
46     print(maxInWindows(ib,3));
47     print(ib);
48 }