Unimodal Sequence

A finite Sequence which first increases and then decreases. A Sequence $\{s_1$, $s_2$, ..., $s_n\}$ is unimodal if there exists a $t$ such that

$$s_1\leq s_2\leq\ldots\leq s_t$$

and

$$s_t\geq s_{t+1}\geq \ldots \geq s_n.$$