【笔记】和算法无关的那些东东

可变参数函数

以不定参数求和为例

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 int sum2(initializer_list<int>il){
 4     int sum=0;
 5     for(auto it=il.begin();it!=il.end();it++){
 6     sum += *it;
 7     }
 8     return sum;
 9 }
10 int sum(int count,...){
11     va_list ap;
12     va_start(ap,count);
13     int sum=0;
14     for(int i=0;i<count;i++){
15     sum+=va_arg(ap,int);
16     }
17     va_end(ap);
18     return sum;
19 }
20 
21 int main(){
22     cout<<sum(3,1,2,5)<<endl;
23     cout<<sum2({1,2,5})<<endl;
24 }

分数类

1 struct Rat {
2   LL a, b;
3   Rat(LL a=0):a(a),b(1) { }
4   Rat(LL x, LL y):a(x),b(y) {
5     if(b < 0) a = -a, b = -b;
6     LL d = __gcd(a, b); if(d < 0) d = -d;
7     a /= d; b /= d;
8   }
9 };

 Int128

 1 struct Int_128{
 2     unsigned long long a,b;
 3     Int_128(ll x){a=0,b=x;}
 4     friend bool operator < (Int_128 x,Int_128 y)
 5     {
 6         return x.a<y.a||x.a==y.a&&x.b<y.b;
 7     }
 8     friend Int_128 operator + (Int_128 x,Int_128 y)
 9     {
10         Int_128 re(0);
11         re.a=x.a+y.a+(x.b+y.b<x.b);
12         re.b=x.b+y.b;
13         return re;
14     }
15     friend Int_128 operator - (Int_128 x,Int_128 y)
16     {
17         y.a=~y.a;y.b=~y.b;
18         return x+y+1;
19     }
20     void Div2()
21     {
22         b>>=1;b|=(a&1ll)<<63;a>>=1;
23     }
24     friend Int_128 operator * (Int_128 x,Int_128 y)
25     {
26         Int_128 re=0;
27         while(y.a||y.b)
28         {
29             if(y.b&1)re=re+x;
30             x=x+x;y.Div2();
31         }
32         return re;
33     }
34     friend Int_128 operator % (Int_128 x,Int_128 y)
35     {
36         Int_128 temp=y;
37         int cnt=0;
38         while(temp<x)temp=temp+temp,++cnt;
39         for(;cnt>=0;cnt--)
40         {
41             if(temp<x)x=x-temp;
42             temp.Div2();
43         }
44         return x;
45     }
46 };

 

posted @ 2018-09-30 14:10  Greenty  阅读(207)  评论(0)  编辑  收藏  举报