1833. Maximum Ice Cream Bars

It is a sweltering summer day, and a boy wants to buy some ice cream bars.

At the store, there are `n` ice cream bars. You are given an array `costs` of length `n`, where `costs[i]` is the price of the `ith` ice cream bar in coins. The boy initially has `coins` coins to spend, and he wants to buy as many ice cream bars as possible.

Return the maximum number of ice cream bars the boy can buy with `coins` coins.

Note: The boy can buy the ice cream bars in any order.

Example 1:

```Input: costs = [1,3,2,4,1], coins = 7
Output: 4
Explanation: The boy can buy ice cream bars at indices 0,1,2,4 for a total price of 1 + 3 + 2 + 1 = 7.
```

Example 2:

```Input: costs = [10,6,8,7,7,8], coins = 5
Output: 0
Explanation: The boy cannot afford any of the ice cream bars.
```

Example 3:

```Input: costs = [1,6,3,1,2,5], coins = 20
Output: 6
Explanation: The boy can buy all the ice cream bars for a total price of 1 + 6 + 3 + 1 + 2 + 5 = 18.
```

Constraints:

• `costs.length == n`
• `1 <= n <= 105`
• `1 <= costs[i] <= 105`
• `1 <= coins <= 108`

1833. Maximum Ice Cream Bars
``````struct Solution;

impl Solution {
fn max_ice_cream(mut costs: Vec<i32>, mut coins: i32) -> i32 {
costs.sort_unstable();
costs.reverse();
let mut res = 0;
while coins > 0 {
if let Some(cheapest) = costs.pop() {
if cheapest <= coins {
coins -= cheapest;
res += 1;
} else {
break;
}
} else {
break;
}
}
res
}
}

#[test]
fn test() {
let costs = vec![1, 3, 2, 4, 1];
let coins = 7;
let res = 4;
assert_eq!(Solution::max_ice_cream(costs, coins), res);

let costs = vec![10, 6, 8, 7, 7, 8];
let coins = 5;
let res = 0;
assert_eq!(Solution::max_ice_cream(costs, coins), res);

let costs = vec![1, 6, 3, 1, 2, 5];
let coins = 20;
let res = 6;
assert_eq!(Solution::max_ice_cream(costs, coins), res);
}
``````