题解 | 乘积为正数的最长连续子数组

#include <iostream>
#include <vector>
using namespace std;

int getMaxLen(vector<int>& nums) {
    int maxLen = 0;
    int pos = 0;  // 正积长度
    int neg = 0;  // 负积长度
    
    for(int num : nums) {
        if(num > 0) {
            pos++;
            neg = neg == 0 ? 0 : neg + 1;
        }
        else if(num < 0) {
            int newPos = neg == 0 ? 0 : neg + 1;
            int newNeg = pos + 1;
            pos = newPos;
            neg = newNeg;
        }
        else {
            pos = 0;
            neg = 0;
        }
        maxLen = max(maxLen, pos);
    }
    
    return maxLen;
}

int main() {
    int n;
    cin >> n;
    vector<int> nums(n);
    for(int i = 0; i < n; i++) {
        cin >> nums[i];
    }
    cout << getMaxLen(nums) << endl;
    return 0;
}

import java.util.Scanner;

public class Main {
    public static int getMaxLen(int[] nums) {
        int maxLen = 0;
        int pos = 0;  // 正积长度
        int neg = 0;  // 负积长度
        
        for(int num : nums) {
            if(num > 0) {
                pos++;
                neg = neg == 0 ? 0 : neg + 1;
            }
            else if(num < 0) {
                int newPos = neg == 0 ? 0 : neg + 1;
                int newNeg = pos + 1;
                pos = newPos;
                neg = newNeg;
            }
            else {
                pos = 0;
                neg = 0;
            }
            maxLen = Math.max(maxLen, pos);
        }
        
        return maxLen;
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] nums = new int[n];
        for(int i = 0; i < n; i++) {
            nums[i] = sc.nextInt();
        }
        System.out.println(getMaxLen(nums));
        sc.close();
    }
}

def get_max_len(nums):
    max_len = 0
    pos = 0  # 正积长度
    neg = 0  # 负积长度
    
    for num in nums:
        if num > 0:
            pos += 1
            neg = 0 if neg == 0 else neg + 1
        elif num < 0:
            new_pos = 0 if neg == 0 else neg + 1
            new_neg = pos + 1
            pos = new_pos
            neg = new_neg
        else:
            pos = 0
            neg = 0
        max_len = max(max_len, pos)
    
    return max_len

n = int(input())
nums = list(map(int, input().split()))
print(get_max_len(nums))