滑动窗口的最大值

题目描述

给定一个数组和滑动窗口的大小，找出所有滑动窗口里数值的最大值。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，他们的最大值分别为{4,4,6,6,6,5}； 针对数组{2,3,4,2,6,2,5,1}的滑动窗口有以下6个： {[2,3,4],2,6,2,5,1}， {2,[3,4,2],6,2,5,1}， {2,3,[4,2,6],2,5,1}， {2,3,4,[2,6,2],5,1}， {2,3,4,2,[6,2,5],1}， {2,3,4,2,6,[2,5,1]}。

class Solution {
public:
    vector<int> maxInWindows(const vector<int>& num, unsigned int size)
{
	vector<int> ans;
	if (size> num.size())
		return ans;

	int low = 0, fast = low + size - 1;
	int curMax = num[0], pos = 0;
	int first = true;
	for (; fast<num.size(); fast++,low++)
	{
		if (pos >= low && !first) //zainei
		{
			if (curMax<num[fast])
			{
				curMax = num[fast];
				pos = fast;
			}
		}
		else
		{
			first = false;
			int move = low;
			curMax = num[move];
			pos = move;
			while (move <= fast)
			{
				if (num[move] >= curMax)
				{
					curMax = num[move];
					pos = move;
				}
				move++;
			}
		}

		ans.push_back(curMax);
	}
	return ans;
}
};