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#1567
Medium Algorithms

Maximum length of subarray with positive product

Array Dynamic Programming Greedy
44.6% acceptance
Feb 25, 2026
2491
80
Given an array of integers nums, find the maximum length of a subarray where the product of all its elements is positive. A subarray of an array is a consecutive sequence of zero or more values taken from that array. Return the maximum length of a subarray with positive product.

Solution

Rust
Time O(n)
Space O(1)
LeetCode
solution.rs 
impl Solution {
  pub fn get_max_len(nums: Vec<i32>) -> i32 {
    let mut pos = 0i32; // length of longest subarray ending here with positive product
    let mut neg = 0i32; // length of longest subarray ending here with negative product
    let mut ans = 0i32;
    for &x in &nums {
      if x > 0 {
        pos = pos + 1;
        neg = if neg > 0 { neg + 1 } else { 0 };
      } else if x < 0 {
        let new_pos = if neg > 0 { neg + 1 } else { 0 };
        neg = pos + 1;
        pos = new_pos;
      } else {
        pos = 0;
        neg = 0;
      }
      ans = ans.max(pos);
    }
    ans
  }
}