洛谷 P1886 滑动窗口 /【模板】单调队列

纯板子题，入队时保证单调性，即单调栈，出队保证题目条件，本题即窗口长度k，在入队出队时都可以维护信息

const int maxm = 1e6+5;

int buf[maxm], maxq[maxm], minq[maxm], ans1[maxm], ans2[maxm];

int main() {
    ios::sync_with_stdio(false), cin.tie(0);
    int n, k, l1 = 0, r1 = -1, l2 = 0, r2 = -1;
    cin >> n >> k;
    for(int i = 0; i < n; ++i)
        cin >> buf[i];
    for(int i = 0; i < n; ++i) {
        while(l1 <= r1 && minq[l1] <= i-k) l1++;
        while(l2 <= r2 && maxq[l2] <= i-k) l2++;
        while(l1 <= r1 && buf[minq[r1]] >= buf[i]) r1--;
        minq[++r1] = i;
        while(l2 <= r2 && buf[maxq[r2]] <= buf[i]) r2--;
        maxq[++r2] = i;
        if(i >= k-1) ans1[i] = buf[minq[l1]], ans2[i] = buf[maxq[l2]];
    }
    for(int i = k-1; i < n; ++i) {
        if(i!=k-1) cout << " ";
        cout << ans1[i];
    }
    cout << "
";
    for(int i = k-1; i < n; ++i) {
        if(i!=k-1) cout << " ";
        cout << ans2[i];
    }
    cout << "
";

    return 0;
}