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#include <algorithm>
#include <iostream>
#include <iterator>
#include <set>
#include <utility>
using namespace std;
const int MOD = 1000000007;
long long get_seg_pairs(int a, int b) {
long long c = b - a + 1;
return c * (c - 1) / 2;
}
int solve() {
// Input.
int N, M;
cin >> N >> M;
long long curr = (long long)N * (N - 1) / 2;
set<pair<int, int>> S;
for (int i = 1; i <= N; i++) {
curr += get_seg_pairs(i, i);
S.emplace(i, i);
}
int ans = 1;
// Process partnerships.
for (int i = 0; i < M; i++) {
int a, b;
cin >> a >> b;
if (a > b) {
swap(a, b);
}
// Find segments containing a and b.
auto it = prev(S.lower_bound({a + 1, 0}));
a = it->first;
b = prev(S.lower_bound({b + 1, 0}))->second;
// Erase all segments between those, inclusive.
while (it != S.end() && it->second <= b) {
curr -= get_seg_pairs(it->first, it->second);
it = S.erase(it);
}
// Insert new merged segment.
curr += get_seg_pairs(a, b);
S.emplace(a, b);
// Update answer.
ans = ans * (curr % MOD) % MOD;
}
return ans;
}
int main() {
int T;
cin >> T;
for (int t = 1; t <= T; t++) {
cout << "Case #" << t << ": " << solve() << endl;
}
return 0;
}
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