public void RMQ_SparseTable()
{
var list = new List <int> {
10, 1, 3, 9, 4, 8, 7
};
var rmq = new RMQSparseTable(list);
Assert.Equal(1, rmq.MinElem(0, 3));
Assert.Equal(1, rmq.MinElem(1, 4));
Assert.Equal(3, rmq.MinElem(2, 5));
}
private static long LargestRec(RMQSparseTable rmq, int l, int r)
{
if (l == r)
{
return(rmq[l]);
}
var minIdx = rmq.MinIdx(l, r);
var minElem = rmq[minIdx];
long maxRect = minElem * (r - l + 1);
if (minIdx - 1 > 0 && l <= minIdx - 1)
{
maxRect = Math.Max(maxRect, LargestRec(rmq, l, minIdx - 1));
}
if (minIdx + 1 < rmq.Count && minIdx + 1 <= r)
{
maxRect = Math.Max(maxRect, LargestRec(rmq, minIdx + 1, r));
}
return(maxRect);
}
static long largestRectangle(int[] h)
{
var rmq = new RMQSparseTable(h);
return(LargestRec(rmq, 0, h.Length - 1));
}
