g2101_2200.s2103_rings_and_rods.Solution Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java21 Show documentation
Java-based LeetCode algorithm problem solutions, regularly updated
There is a newer version: 1.38
package g2101_2200.s2103_rings_and_rods;

// #Easy #String #Hash_Table #2022_05_31_Time_2_ms_(46.84%)_Space_42.2_MB_(29.77%)

import java.util.HashMap;
import java.util.Map;

/**
 * 2103 - Rings and Rods\.
 *
 * Easy
 *
 * 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 i^th pair denotes the i^th ring's **color** (`'R'`, `'G'`, `'B'`).
 * *   The **second** character of the i^th pair denotes the **rod** that the i^th 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:**
 *
 * ![](https://assets.leetcode.com/uploads/2021/11/23/ex1final.png)
 *
 * **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:**
 *
 * ![](https://assets.leetcode.com/uploads/2021/11/23/ex2final.png)
 *
 * **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** ).
**/
public class Solution {
    public int countPoints(String rings) {
        Map redHashMap = new HashMap<>();
        Map greenHashMap = new HashMap<>();
        Map blueHashMap = new HashMap<>();
        for (int i = 0; i <= rings.length() - 2; i = i + 2) {
            char charOne = rings.charAt(i);
            char charTwo = rings.charAt(i + 1);

            if (charOne == 'R') {
                redHashMap.put(Character.getNumericValue(charTwo), 123);
            } else if (charOne == 'G') {
                greenHashMap.put(Character.getNumericValue(charTwo), 123);
            } else {
                blueHashMap.put(Character.getNumericValue(charTwo), 123);
            }
        }
        int result = 0;
        for (int i = 0; i <= 9; i++) {
            if (redHashMap.containsKey(i)
                    && greenHashMap.containsKey(i)
                    && blueHashMap.containsKey(i)) {
                result++;
            }
        }
        return result;
    }
}