800. Similar RGB Color

In the following, every capital letter represents some hexadecimal digit from `0` to `f`.

The red-green-blue color `"#AABBCC"` can be written as `"#ABC"` in shorthand.  For example, `"#15c"` is shorthand for the color `"#1155cc"`.

Now, say the similarity between two colors `"#ABCDEF"` and `"#UVWXYZ"` is `-(AB - UV)^2 - (CD - WX)^2 - (EF - YZ)^2`.

Given the color `"#ABCDEF"`, return a 7 character color that is most similar to `#ABCDEF`, and has a shorthand (that is, it can be represented as some `"#XYZ"`

```Example 1:
Input: color = "#09f166"
Output: "#11ee66"
Explanation:
The similarity is -(0x09 - 0x11)^2 -(0xf1 - 0xee)^2 - (0x66 - 0x66)^2 = -64 -9 -0 = -73.
This is the highest among any shorthand color.
```

Note:

• `color` is a string of length `7`.
• `color` is a valid RGB color: for `i > 0`, `color[i]` is a hexadecimal digit from `0` to `f`
• Any answer which has the same (highest) similarity as the best answer will be accepted.
• All inputs and outputs should use lowercase letters, and the output is 7 characters.

Rust Solution

``````struct Solution;

use std::i32;

impl Solution {
fn most_similar(x: i32) -> i32 {
let mut min = i32::MAX;
let mut res = 0;
for i in 0..16 {
if (x - i * 17).abs() < min {
min = (x - i * 17).abs();
res = i * 17;
}
}
res
}
fn similar_rgb(color: String) -> String {
format!(
"#{:02x}{:02x}{:02x}",
Self::most_similar(r),
Self::most_similar(g),
Self::most_similar(b)
)
}
}

#[test]
fn test() {
let color = "#09f166".to_string();
let res = "#11ee66".to_string();
assert_eq!(Solution::similar_rgb(color), res);
}
``````

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