<800ms

（不要问我事怎样发现的（心虚

const int N = 1e6 + 5;
int n, m, a[N], id[N];
int f[N];
void solve() {
	cin >> n >> m;
	FOR(i, 1, n) cin >> a[i];
	FOR(i, 1, n) id[i] = i;
	sort(id + 1, id + n + 1, [] (int x, int y) {
		return a[x] < a[y];
	});
	ROF(i, n, 1) {
		int u = id[i];
		int l = max(1, u - m);
		FOR(j, l, u) f[j] = 1;
		int c = 0;
		FOR(j, 1, n) {
			if(!f[j]) break;
			c++;
		}
		if(c > n - 1 - m) {
			cout << a[u] << endl;
			return;
		}
	}
}