# 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 > 0color[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.

class Solution {
public:
string similarRGB(string color) {
return "#" + helper(color.substr(1, 2)) + helper(color.substr(3, 2)) + helper(color.substr(5, 2));
}
string helper(string str) {
string dict = "0123456789abcdef";
int num = stoi(str, nullptr, 16);
int idx = num / 17 + (num % 17 > 8 ? 1 : 0);
return string(2, dict[idx]);
}
};

class Solution {
public:
string similarRGB(string color) {
for (int i = 1; i < color.size(); i += 2) {
int num = stoi(color.substr(i, 2), nullptr, 16);
int idx = num / 17 + (num % 17 > 8 ? 1 : 0);
color[i] = color[i + 1] = (idx > 9) ? (idx - 10 + 'a') : (idx + '0');
}
return color;
}
};

https://leetcode.com/problems/similar-rgb-color/solution/

https://leetcode.com/problems/similar-rgb-color/discuss/120077/C++-Concise-Solution-with-explanation-6ms

https://leetcode.com/problems/similar-rgb-color/discuss/120093/C++-O(1)-time-and-space-Easy-to-Understand

LeetCode All in One 题目讲解汇总(持续更新中…)

 微信打赏 Venmo 打赏
（欢迎加入博主的知识星球，博主将及时答疑解惑，并分享刷题经验与总结，试运营期间前五十位可享受半价优惠～）

×

Help us with donation