Practice Frog Jump

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Hard#403

LeetCode Problem

Frog Jump

Array Dynamic Programming

Problem Statement

A frog is crossing a river. The river is divided into some number of units, and at each unit, there may or may not exist a stone. The frog can jump on a stone, but it must not jump into the water. Given a list of stones positions (in units) in sorted ascending order, determine if the frog can cross the river by landing on the last stone. Initially, the frog is on the first stone and assumes the first jump must be 1 unit. If the frog's last jump was k units, its next jump must be either k - 1, k, or k + 1 units. The frog can only jump in the forward direction.

Source: Frog Jump on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input

stones = [0,1,3,5,6,8,12,17]

Output

true

# Example 2

Input

stones = [0,1,2,3,4,8,9,11]

Output

false

Constraints

2 <= stones.length <= 2000

0 <= stones[i] <= 2^31 - 1

stones[0] == 0

stones is sorted in a strictly increasing order.

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