LeetCode Entry

1871. Jump Game VII

25.05.2026 medium 2026 kotlin rust

Can reach end jumping min..max to zeros

1871. Jump Game VII medium substack youtube

https://dmitrysamoylenko.com/leetcode/

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Problem TLDR

Can reach end jumping min..max to zeros

Intuition

• forward: put line sweep interval start-end events, slide
• backwards: slide window looking backwards, count reachable items inside window

Approach

• the end should not be ‘1’

Complexity

• Time complexity: \(O(n)\)

• Space complexity: \(O(n)\)

Code

    fun canReach(s: String, min: Int, max: Int): Boolean {
        val e = IntArray(s.length+max+2); e[1] = -1
        return s.last() == '0' && 0 < s.indices.fold(1) { c, i ->
            if (s[i] == '0' && c+e[i] > 0) { e[i+min]++; e[i+max+1]-- }
            c + e[i]
        }
    }

    pub fn can_reach(s: String, l: i32, h: i32) -> bool {
        let mut e = vec![0; s.len()+h as usize + 2]; e[1] = -1;
        s.ends_with('0') && 0 < s.bytes().zip(0..).fold(1, |c, (v, i)| {
            if v < 49 && c + e[i] > 0 { e[i+l as usize] += 1; e[i+h as usize+1] -= 1 }
            c + e[i]
        })
    }