# 1230. Toss Strange Coins

<https://leetcode.com/problems/toss-strange-coins>

## Description

You have some coins.  The `i`-th coin has a probability `prob[i]` of facing heads when tossed.

Return the probability that the number of coins facing heads equals `target` if you toss every coin exactly once.

**Example 1:**

```
**Input:** prob = [0.4], target = 1
**Output:** 0.40000
```

**Example 2:**

```
**Input:** prob = [0.5,0.5,0.5,0.5,0.5], target = 0
**Output:** 0.03125
```

**Constraints:**

* `1 <= prob.length <= 1000`
* `0 <= prob[i] <= 1`
* `0 <= target``<= prob.length`
* Answers will be accepted as correct if they are within `10^-5` of the correct answer.

## ac

```java
```