# [Leet Code] Rings and Rods

--

Leetcode: https://leetcode.com/problems/rings-and-rods/

Problem:

There are `n`

rings and each ring is either red, green, or blue. The rings are distributed **across ten rods** labeled from `0`

to `9`

.

You are given a string `rings`

of length `2n`

that describes the `n`

rings that are placed onto the rods. Every two characters in `rings`

forms a **color-position pair** that is used to describe each ring where:

- The
**first**character of the`ith`

pair denotes the`ith`

ring's**color**(`'R'`

,`'G'`

,`'B'`

). - The
**second**character of the`ith`

pair denotes the**rod**that the`ith`

ring is placed on (`'0'`

to`'9'`

).

For example, `"R3G2B1"`

describes `n == 3`

rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.

Return *the number of rods that have **all three colors** of rings on them.*

**Example 1:**

**Input:** rings = "B0B6G0R6R0R6G9"

**Output:** 1

**Explanation:**

- The rod labeled 0 holds 3 rings with all colors: red, green, and blue.

- The rod labeled 6 holds 3 rings, but it only has red and blue.

- The rod labeled 9 holds only a green ring.

Thus, the number of rods with all three colors is 1.

**Example 2:**

**Input:** rings = "B0R0G0R9R0B0G0"

**Output:** 1

**Explanation:**

- The rod labeled 0 holds 6 rings with all colors: red, green, and blue.

- The rod labeled 9 holds only a red ring.

Thus, the number of rods with all three colors is 1.

**Example 3:**

**Input:** rings = "G4"

**Output:** 0

**Explanation:**

Only one ring is given. Thus, no rods have all three colors.

**Constraints:**

`rings.length == 2 * n`

`1 <= n <= 100`

`rings[i]`

where`i`

is**even**is either`'R'`

,`'G'`

, or`'B'`

(**0-indexed**).`rings[i]`

where`i`

is**odd**is a digit from`'0'`

to`'9'`

(**0-indexed**).

Solution:

func countPoints(rings string) int {

hashMap := make(map[string][]string)

counter := 0

for i := 0; i < len(rings); i+= 2{

letter := string(rings[i])

number := string(rings[i+1])

hashMap[number] = append(hashMap[number], letter)

}

fmt.Println(hashMap)

for number := range hashMap{

if len(unique(hashMap[number])) == 3{

counter += 1

}

}

return counter

}func unique(intSlice []string) []string {

keys := make(map[string]bool)

list := []string{}

for _, entry := range intSlice {

if _, value := keys[entry]; !value {

keys[entry] = true

list = append(list, entry)

}

}

return list

}