Jump Game II
You are given a 0-indexed array of integers nums of length n. You are initially positioned at nums[0].
Each element nums[i] represents the maximum length of a forward jump from index i. In other words, if you are at nums[i], you can jump to any nums[i + j] where:
0 <= j <= nums[i] and
i + j < n
Return the minimum number of jumps to reach nums[n - 1]. The test cases are generated such that you can reach nums[n - 1].
class Solution:
def jump(self, nums: List[int]) -> int:
size = len(nums)
# destination is last index
destination = size - 1
# record of current coverage, record of last jump index
cur_coverage, last_jump_index = 0, 0
# counter for jump
times_of_jump = 0
# Quick response if start index == destination index == 0
if size == 1:
return 0
# Greedy strategy: extend coverage as long as possible with lazy jump
for i in range( 0, size):
# extend current coverage as further as possible
cur_coverage = max( cur_coverage, i + nums[i] )
# forced to jump (by lazy jump) to extend coverage
if i == last_jump_index:
# update last jump index
last_jump_index = cur_coverage
# update counter of jump by +1
times_of_jump += 1
# check if reached destination already
if cur_coverage >= destination:
return times_of_jump
return times_of_jumpPosted by Jamie Meyer 15 days ago