Help me in solving COUNTWINSUB problem

help
,
1

My issue

on the input 0011, the expected output is 5 but it should be 4, that’s why wrong answer is coming.Anyone else facing the same issue?

My code

#include <bits/stdc++.h>
using namespace std;
vector<int> bt;
int bitSum(int i,vector<int> &bt)
{
    int sum = 0;
    for (i = i + 1; i > 0; i -= i & (-i))
        sum += bt[i];
    return sum;
}
void bitUpdate(int i, int val,vector<int> &bt)
{
    for (i = i + 1; i <= 400000; i += i & (-i))
        bt[i] += val;
}    
int subarraysWithMoreZerosThanOnes(vector<int>& nums,vector<int> &bt) {
    int res = 0, bal = 0;
    bitUpdate(200000, 1,bt);
    for (int num : nums) {
        bal += num ? 1 : -1;
        bitUpdate(bal + 200000, 1,bt);
        res = (res + bitSum(bal + 200000 - 1,bt)) % 1000000007;
    }
    return res;
}
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        vector<int> bt(400001,0);
        vector<int> input;
        for(int i=0;i<n;i++)
        {
            int element;
            cin>>element;
            input.push_back(element);
        }
        cout<<subarraysWithMoreZerosThanOnes(input,bt)<<endl;
    }
}

Problem Link: Count Winning Subarrays Practice Coding Problem

2

Not your fault, this question is very poorly framed and proper explanation is not given.
Here in array 0011 after operation on L=2, R=4 we can do L=1, R=4 as now array is 0111. Although this is not at all properly explained in the problem.
But again with a twist you can only move in a direction in subarray not move in reverse.
Example
in array 1010
L=1, R=4 is a wining subarray but L=2,R=2 is not as it was changed after L=1, R=3.
So all this is just picked from the solutions of others and this problem statement and solution is a complete trash.