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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5. #define print(a)         for(auto x : a) cout << x << " "; cout << endl
  6.  
  7.  
  8. const int M = 1000000007;
  9. const int N = 3e5+9;
  10. const int INF = 2e9+1;
  11. const int LINF = 2000000000000000001;
  12.  
  13. inline int power(int a, int b, int mod=M) {
  14.     int x = 1;
  15.     a %= mod;
  16.     while (b) {
  17.         if (b & 1) x = (x * a) % mod; 
  18.         a = (a * a) % mod;
  19.         b >>= 1;
  20.     }
  21.     return x;
  22. }
  23.  
  24.  
  25. //_ ***************************** START Below *******************************
  26.  
  27.  
  28. vector<int> fact(N+1);
  29. vector<int> iFact(N+1);
  30.  
  31.  
  32. void compute(){
  33. 	fact[0] = 1;
  34.  
  35. 	for(int i=1; i<=N; i++){
  36. 		fact[i] = ( fact[i-1] * i%M )%M;
  37. 	}
  38.  
  39. 	//* TC = O( N * logM )
  40. 	// iFact[0] = 1;
  41. 	// for(int i=1; i<=N; i++){
  42. 	// 	iFact[i] = power(fact[i], M-2, M);
  43. 	// }
  44.  
  45. 	//* TC = O( N + logM )
  46. 	iFact[N] = power(fact[N], M-2, M);
  47. 	for(int i=N-1; i>=0; i--){
  48. 		iFact[i] = (iFact[i+1] * (i+1))%M;
  49. 	}
  50.  
  51.  
  52. }
  53.  
  54.  
  55.  
  56.  
  57. //* Case 1 : n <= 1e6  &&  r <= 1e6
  58.  
  59. int nCr(int n, int r){
  60. 	if(r>n || r<0) return 0;
  61.  
  62. 	return (fact[n] * ( iFact[r]%M * iFact[n-r]%M )%M ) % M;
  63. }
  64.  
  65.  
  66. int consistency(int n, int r){
  67.  
  68. 	return nCr(n, r);
  69.  
  70. }
  71.  
  72.  
  73.  
  74.  
  75.  
  76.  
  77.  
  78.  
  79.  
  80.  
  81.  
  82.  
  83.  
  84.  
  85.  
  86. int practice(int n, int r){
  87.  
  88.  
  89.  
  90.     return 0;
  91. }
  92.  
  93.  
  94.  
  95.  
  96.  
  97. void solve() {
  98.  
  99.     static int _ = (compute(), 0);
  100.  
  101.     int n, r;
  102.     cin>> n >> r;
  103.  
  104.  
  105.     cout << consistency(n, r) << endl;
  106.  
  107.  
  108. }
  109.  
  110.  
  111.  
  112.  
  113.  
  114. int32_t main() {
  115.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  116.  
  117.     int t = 1;
  118.     cin >> t;
  119.     while (t--) {
  120.         solve();
  121.     }
  122.  
  123.     return 0;
  124. }
Success #stdin #stdout 0.04s 7792KB
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https://ideone.com/p13wRD
language:
C++14 (gcc 8.3)
created:
20 hours ago
visibility:
public

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