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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
  5.  
  6. #define int long long
  7. #define pb push_back
  8. #define ff first
  9. #define ss second
  10. #define all(x) (x).begin(), (x).end()
  11. #define rall(x) (x).rbegin(), (x).rend()
  12. #define sz(x) ((int)(x).size())
  13. #define endl '\n'
  14. #define yes cout << "yes\n"
  15. #define no cout << "no\n"
  16.  
  17. #define rep(i,a,b) for(int i=a;i<b;++i)
  18. #define per(i,a,b) for(int i=b-1;i>=a;--i)
  19. #define each(x, a) for (auto& x : a)
  20.  
  21. const int INF = 1e18;
  22. const int MOD = 998244353;
  23. const int N = 3e5 + 5;
  24.  
  25. int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
  26. int lcm(int a, int b) { return (a / gcd(a, b)) * b; }
  27.  
  28. int power(int a, int b, int m = MOD) {
  29.     int res = 1;
  30.     while (b > 0) {
  31.         if (b & 1) res = res * a % m;
  32.         a = a * a % m;
  33.         b >>= 1;
  34.     }
  35.     return res;
  36. }
  37.  
  38. int modinv(int a, int m = MOD) {
  39.     return power(a, m - 2, m);
  40. }
  41.  
  42. void solve() {
  43.     int n, m;
  44.     cin >> n >> m;
  45.     vector<int> limit(n + 1, 0);
  46.     rep(i, 0, m) {
  47.         int l, r;
  48.         cin >> l >> r;
  49.         limit[r] = max(limit[r], l);
  50.     }
  51.     rep(i, 1, n + 1) {
  52.         limit[i] = max(limit[i], limit[i - 1]);
  53.     }
  54.     vector<int> dp(n + 1, 0);
  55.     vector<int> sdp(n + 1, 0);
  56.     dp[0] = 1;
  57.     sdp[0] = 1;
  58.     rep(i, 1, n + 1) {
  59.         int l = limit[i];
  60.         int r = i - 1;
  61.         if (l <= r) {
  62.             int current_sum = sdp[r];
  63.             int prev_sum = (l > 0) ? sdp[l - 1] : 0;
  64.             dp[i] = (current_sum - prev_sum + MOD) % MOD;
  65.         } else {
  66.             dp[i] = 0;
  67.         }
  68.         sdp[i] = (sdp[i - 1] + dp[i]) % MOD;
  69.     }
  70.     cout << (2 * dp[n]) % MOD << endl;
  71. }
  72.  
  73. int32_t main() {
  74.     fast_io;
  75.  
  76.     int t;
  77.     cin >> t;
  78.     while (t--) {
  79.         solve();
  80.     }
  81.  
  82.     return 0;
  83. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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3
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stdout
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2
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570529459
https://ideone.com/pjKZ9Q
language:
C++ (gcc 8.3)
created:
17 hours ago
visibility:
public

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