标签:style blog color os io for 2014 div
今天见识到了“数学上来先打表”............
#include<iostream> using namespace std; #include<iomanip> #define LL long long /* int lowbit(int n) { int t,cnt = 1; t = n % 2; if(t == 1) return 1; while(t == 0) { cnt *= 2; n /= 2; t = n % 2; } return cnt; } LL d(int n) { LL ans = 0; for(int i = 1; i <= n; i++) ans += lowbit(i); return ans; } */ //经过打表,得f(x) = 2 * f( x / 2) + n / 2 + ( n & 1 ) LL d(int n) { if(n == 1)return 1; LL ans = 2 * d(n / 2) + n / 2 + (n & 1); return ans; } int main() { int n; while(cin>>n) { cout<<d(n)<<endl; } return 0; }
acdream 20140730 D题,布布扣,bubuko.com
标签:style blog color os io for 2014 div
原文地址:http://www.cnblogs.com/imLPT/p/3879689.html