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| #include <bits/stdc++.h>
#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
struct PairHash {inline std::size_t operator()(const std::pair<int,int> & v) const {return v.first*31+v.second;}};
#define MAX_N 10101
#define INF 987654321
#define EPS 1e-9
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all3 array<ll,3>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vi vector<int>
#define vs vector<string>
#define usll unordered_set<ll>
#define uspll unordered_set<pll, PairHash>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
using namespace std;
ll mod = 1e9 + 7;
ll dp[MAX_N];
ll dpp[MAX_N];
ll modpow(ll n, ll x) {
if(x == 0) return 1;
ll res = modpow(n, x>>1);
res = res * res % mod;
if(x & 1) res = res * n % mod;
return res;
}
ll solve(ll n, ll m) {
memset(dp, 0, sizeof dp);
for(ll i = 0; i < min(m, 4ll); i++) dp[i] = 1;
for(ll i = 0; i < m; i++) {
for (ll j = 1; j <= 4; j++)
dp[i + j] = (dp[i + j] + dp[i]) % mod;
dpp[i] = modpow(dp[i], n);
}
vll res(m);
for(ll i = 0; i < m; i++) {
res[i] = dpp[i];
for(ll j = 0; j < i; j++) {
res[i] = (res[i] - res[j] * dpp[i-j-1] % mod + mod) % mod;
}
}
return res[m-1];
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
cin>>tc;
for(ll i = 1; i <= tc; i++) {
ll n, m;
cin>>n>>m;
cout<<solve(n,m)<<endl;
}
return 0;
}
|
