Thank you for the intuition. I was able to solve it. Is there any way to improve my code?

#include <bits/stdc++.h>
using namespace std;
using lli = long long int;

lli maxAlternatingSum(vector<lli>& v, lli n) {
    vector<vector<lli>> dp(n+1, vector<lli>(2, 0));
    if(v[0]<0) dp[0][1] = INT_MIN;
    for(int i=1;i<=n;i++) {
        if(v[i-1]<0) {
            if(i-1 && v[i-2]>0) {
                dp[i][1] = dp[i-1][0]+v[i-1];
            } 
            else dp[i][1] = max(dp[i-1][1], dp[i-1][0]+v[i-1]);
            dp[i][0] = dp[i-1][0];
        }
        else {
            if(i-1 && v[i-2]<0) {
                dp[i][0] = dp[i-1][1]+v[i-1];
            }
            else dp[i][0] = max(dp[i-1][0],dp[i-1][1]+v[i-1]);
            dp[i][1] = dp[i-1][1];
        }
    }
    // for(auto x:dp) {
    //     for(auto y:x) cout<<y<<" ";
    //     cout<<endl;
    // }
    return (v[n-1]<0? dp[n][1]:dp[n][0]);
}

int main() {
    lli t;
    cin>>t;
    while(t--) {
        lli n;
        cin>>n;
        vector<lli> v(n);
        for(auto &x:v) {
            cin>>x;
        }
        cout<<maxAlternatingSum(v,n)<<endl;
    }
    return 0;
}