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  1. #include <iostream>
  2. #include <complex>
  3. #include <cstdlib>
  4.  
  5. using namespace std;
  6.  
  7. int D[500100];
  8. int FF[500100];
  9.  
  10. typedef complex<double> base;
  11.  
  12. int rev[1100000];
  13. base wlen_pw[1100000];
  14. long double PI = 3.14159265354;
  15. int n = 1048576;
  16. base fa[1048576];
  17. base fb[1048576];
  18.  
  19. void fft (base a[], bool invert) {
  20.         for (int i=0; i<n; ++i)
  21.                 if (i < rev[i])
  22.                         swap (a[i], a[rev[i]]);
  23.  
  24.         for (int len=2; len<=n; len<<=1) {
  25.                 double ang = 2*PI/len * (invert?-1:+1);
  26.                 int len2 = len>>1;
  27.  
  28.                 base wlen (cos(ang), sin(ang));
  29.                 wlen_pw[0] = base (1, 0);
  30.                 for (int i=1; i<len2; ++i)
  31.                         wlen_pw[i] = wlen_pw[i-1] * wlen;
  32.  
  33.                 for (int i=0; i<n; i+=len) {
  34.                         base t,
  35.                                 *pu = a+i,
  36.                                 *pv = a+i+len2, 
  37.                                 *pu_end = a+i+len2,
  38.                                 *pw = wlen_pw;
  39.                         for (; pu!=pu_end; ++pu, ++pv, ++pw) {
  40.                                 t = *pv * *pw;
  41.                                 *pv = *pu - t;
  42.                                 *pu += t;
  43.                         }
  44.                 }
  45.         }
  46.  
  47.         if (invert)
  48.                 for (int i=0; i<n; ++i)
  49.                         a[i] /= n;
  50. }
  51.  
  52. void calc_rev () {
  53.         for (int i=0; i<n; ++i) {
  54.                 rev[i] = 0;
  55.                 for (int j=0; j<20; ++j)
  56.                         if (i & (1<<j))
  57.                                 rev[i] |= 1<<(19-j);
  58.         }
  59. }
  60.  
  61. void multiply () {
  62.  
  63.         for (int i=0;i<500001;i++)
  64.                 fa[i] = D[i];
  65.         for (int i=0;i<500001;i++)
  66.                 fb[i] = D[i];   
  67.  
  68.         fft (fa, false);
  69.         fft (fb, false);
  70.         for (size_t i=0; i<n; ++i)
  71.                 fa[i] *= fb[i];
  72.         fft (fa, true);
  73.  
  74.  
  75.         for (size_t i=0; i<500001; ++i)
  76.                 FF[i] = int (fa[i].real() + 0.5);
  77. }
  78.  
  79.  
  80. int main(){
  81.   D[1] = 1;
  82.   for (int i=2;i<=500000;i++)
  83.         if (!D[i])
  84.                 for (int j=i+i;j<=500000;j+=i)
  85.                         D[j] = i;
  86.  
  87.   for (int i=500000;i>=2;i--){
  88.      int d = 1;
  89.      int u = i; 
  90.      int b = D[u];
  91.      int c = 0;
  92.      while (D[u]){
  93.         if (b == D[u])
  94.                 c++;
  95.         else{
  96.             d*=(c+1);
  97.             c = 1;
  98.             b = D[u];
  99.         }
  100.         u/=D[u];
  101.      }  
  102.      if (u == b)
  103.              d*=(c+2);
  104.      else d*=(c+1)*2;
  105.      D[i] = d; 
  106.   }
  107.   calc_rev();
  108.   multiply();
  109.  
  110.  
  111.   int N;
  112.   cin >> N;
  113.   for (int i=0;i<N;i++){
  114.      int l,r;
  115.      cin >> l >> r;
  116.      int aa = 0;
  117.      int v = -1;
  118.      for (int j=l;j<=r;j++)
  119.         if (aa < FF[j]){
  120.                 aa = FF[j];
  121.                 v = j;
  122.         }
  123.         cout << v << " "<<aa<<endl;
  124.   } 
  125. }
Success #stdin #stdout 2.36s 61264KB
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https://ideone.com/hwsgRh
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
secret

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