Sliding Window

Feature: look back into data in a certain range in a shifting way.

// @k: size of sliding window
void sliding_window(const vector<int>& vec, const int k) {
    int tot = 0; // total sum in the sliding window
    for(int i=0; i<vec.size(); i++) {
        /*
        Do operation to window vec[max(i-k,0):i-1]
        */
        tot += vec[i]; 
        if(i>=k) tot -= vec[i-k];
        /*
        Do operation to window vec[max(i-k+1,0):i] 
        */
    }
}