#include <iostream>

#include <vector>

using namespace std;

long long triple_removal_cost(const vector<int>& a) {

// Group 0 and 1 indices separately

vector<int> zeros, ones;

for (int i = 0; i < (int)a.size(); i++) {

if (a[i] == 0)

zeros.push_back(i);

else

ones.push_back(i);

}

if (zeros.size() % 3 != 0 || ones.size() % 3 != 0)

return -1;

long long ans = 0;

auto calc = [&](const vector<int>& v) -> long long {

long long cost = 0;

for (size_t i = 0; i + 2 < v.size(); i += 3) {

cost += min(v[i + 1] - v[i], v[i + 2] - v[i + 1]);

}

return cost;

};

ans += calc(zeros);

ans += calc(ones);

return ans;

}

int main() {

ios::sync_with_stdio(false);

cin.tie(nullptr);

int t; cin >> t;

while (t--) {

int n, q; cin >> n >> q;

vector<int> a(n);

for (int i = 0; i < n; i++) cin >> a[i];

while (q--) {

int l, r; cin >> l >> r;

l--, r--;

vector<int> sub(a.begin() + l, a.begin() + r + 1);

cout << triple_removal_cost(sub) << "\n";

}

}

return 0;

}