题解 | 滑动窗口的最大值

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param num int整型vector 
     * @param size int整型 
     * @return int整型vector
     */
    vector<int> maxInWindows(vector<int>& num, int size) {
        // write code here
        deque<int> q;
        vector<int> result;
        if (size == 0) {
            return {};
        }
        for (int i = 0; i < num.size(); i++) {
            while (!q.empty() && num[i] > num[q.back()]) {
                // cout << "pop back " << q.back() << endl;
                q.pop_back();
            }

            q.push_back(i);
            // cout << "push back " << i << endl;

            if (i >= size && (q.front() == i-size)) {
                q.pop_front();
                // cout << "pop front " << num[i-size] << endl;
            }
            if (i >= size - 1) {
                result.push_back(num[q.front()]);
                // cout << "max: " << num[q.front()] << endl;
            }
        }
        return result;
    }
};