Jump Game IV

arrayhash tablebreadth-first search

Problem Statement

Given an array of integers arr , you are initially positioned at the first index of the array.

In one step you can jump from index i to index:

i + 1 where: i + 1 < arr.length .

i - 1 where: i - 1 >= 0 .

j where: arr[i] == arr[j] and i != j .

Return the minimum number of steps to reach the last index of the array.

Notice that you can not jump outside of the array at any time.

Examples

Example 1

Input: arr = [100,-23,-23,404,100,23,23,23,3,404]
Output: 3
You need three jumps from index 0 --> 4 --> 3 --> 9. Note that index 9 is the last index of the array.

Example 2

Input: arr = [7]
Output: 0
Start index is the last index. You do not need to jump.

Example 3

Input: arr = [7,6,9,6,9,6,9,7]
Output: 1
You can jump directly from index 0 to index 7 which is last index of the array.

Constraints

1 <= arr.length <= 5 * 10 ^4

-10 ^8 <= arr[i] <= 10 ^8

😤

Hard

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicHash Table