#2770

Maximum Number of Jumps to Reach the Last Index

Medium
ArrayDynamic ProgrammingDynamic ProgrammingGreedy Algorithms
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Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution
Time
O(n²)
O(n²)
Space
O(n)
O(n)
💡

Intuition

Time O(n²)Space O(n)

The optimal approach uses dynamic programming to store the maximum number of jumps to each index. This way, we avoid redundant calculations and efficiently find the solution.

⚙️

Algorithm

3 steps
  1. 1Step 1: Initialize a dp array of size n with all values set to -1, except dp[0] which is set to 0.
  2. 2Step 2: Iterate through each index i from 0 to n-1.
  3. 3Step 3: For each index i, check all possible jumps to index j (i < j < n) that satisfy the target condition and update dp[j] accordingly.
solution.py13 lines
1# Full working Python code
2
3def maxJumps(nums, target):
4    n = len(nums)
5    dp = [-1] * n
6    dp[0] = 0
7    for i in range(n):
8        if dp[i] == -1:
9            continue
10        for j in range(i + 1, n):
11            if nums[j] - nums[i] <= target:
12                dp[j] = max(dp[j], dp[i] + 1)
13    return dp[-1]

Complexity note: The time complexity remains O(n²) due to the nested loops, but we significantly reduce redundant calculations by storing results. The space complexity is O(n) for the dp array.

  • 1Dynamic programming helps avoid redundant calculations.
  • 2Understanding the jump conditions is crucial for optimizing the solution.

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