题解 | #乘积为正数的最长连续子数组#

#include <any>
#include <iostream>
#include <utility>
using namespace std;

int main() {
    int max_l = 0, min_l = 0, max_dp = 1, min_dp = 1;
    int n, a;
    cin >> n;
    int ans = 0;
    for (int i = 0; i < n; i++) {
        cin >> a;
        if (a == 0) {
            // 重置
            max_l = 0, min_l = 0, max_dp = 1, min_dp = 1;
        } else if (a < 0) {
            a = -1; // 简化防止溢出
            swap(max_dp, min_dp); // 交换最大最小
            swap(max_l, min_l);
        } else {
            a = 1;
        }
        if (max_dp * a > 0) {
            max_l++;
            max_dp *= a;
        } else { // 重置
            max_l = 0;
            max_dp = 1;
        }
        if (min_dp * a < 0) {
            min_l++;
            min_dp *= a;
        } else { // 重置
            min_l = 0;
            min_dp = 1;
        }
        // cout << "max_l: " << max_l << " min_l: " << min_l << endl;
        ans = max(ans, max_l);
    }
    cout << ans;
}
// 64 位输出请用 printf("%lld")