洛谷 P4317 花神的数论题
题目传送门
数位dp
#include<iostream> #include<cstdio> #include<cstring> using namespace std; long long n,f[70][2][70]; long long s[70],len,mod = 10000007; inline long long max(int a,long long b) { if(a > b) return a; return b; } inline long long dfs(int d,bool li,long long sum) { if(d == 0) return max(1,sum) % mod; if(f[d][li][sum] != -1) return f[d][li][sum] % mod; int res = li ? s[d] : 1; long long num = 1; for(int i = 0;i <= res; i++) (num *= dfs(d - 1,li && i == res,sum + ((i == 1) ? 1 : 0))) %= mod; f[d][li][sum] = num % mod; return num % mod; } inline long long solve(long long x) { len = 0; while(x) { s[++len] = x % 2; x /= 2; } memset(f,-1,sizeof(f)); return dfs(len,1,0); } int main() { scanf("%lld",&n);; printf("%lld",solve(n)); return 0; }