#include <bits/stdc++.h>

#include <atcoder/modint.hpp>
#define reps(i, n) for (int i = 1, i##_len = (n); i <= i##_len; ++i)
using namespace std;
using namespace atcoder;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int Q;
    cin >> Q;
    while (Q--) {
        int n, m;
        cin >> n >> m;
        using mint = modint;
        mint::set_mod(m);
        using mint998 = modint998244353;

        vector<mint> a(n + 1);
        vector<int> b(n + 1);
        reps(i, n) {
            int x;
            cin >> x;
            if (x != -1) a[i] = x;
            else b[i] = 1;
        }
        auto ca = a;
        auto cb = b;
        reps(i, n) ca[i] += ca[i - 1];
        reps(i, n) cb[i] += cb[i - 1];

        mint998 ans = ((cb[n] == 0) ? (ca[n] == 0) : mint998(m).pow(cb[n] - 1)) * (n - 1);
        reps(i, n - 1) {
            mint lSum = ca[i], rSum = ca[n] - lSum;
            int lCnt = cb[i], rCnt = cb[n] - lCnt;
            mint998 lNum = (lCnt == 0) ? (lSum == 0) : mint998(m).pow(lCnt - 1);
            mint998 rNum = (rCnt == 0) ? (rSum == 0) : mint998(m).pow(rCnt - 1);
            ans -= lNum * rNum;
        }
        cout << ans.val() << endl;
    }

    return 0;
}