卡常数

运算符号

本机CPU: 13th Gen Intel(R) Core(TM) i5-1340P 1.90 GHz

编译器：gcc:g++ (Rev2, Built by MSYS2 project) 14.2.0,c++17

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
signed main(){
    ll A=1;
    for(ll i=1;i<=1000000000;++i){
        A+=(formula...);
    }
    cout<<A<<endl;
    return 0;
}

\(10^9\) 次同种运算，赋值运算影响忽略。

operation	time1	time2	time3
only +=	1694	1725	1707
ll + ll	1687	1702	1710
ll - ll	1714	1690	1715
ll * ll and ll %	3226	3196	3225
ll / ll	3419	3415	3455
ll >>	1390	1378	1381
ll <<	1381	1396	1387
ll & ll	1721	1688	1701
ll | ll	1718	1710	1726
ll ^ ll	1710	1730	1703
ll++	1687	1679	1658
++ll	1477	1473	1468
ll % ll(int)	2325	2299	2293
ll < ll (>)	1446	1472	1489
ll == ll (!=)	1434	1464	1456
ll && ll (logic)	1440	1417	1427
ll ? ll : ll	1406	1422	1394

读写

template<typename T>
void read(T &a){
	#define gc getchar()
	char c;a=0;int f=1;
	while(!isdigit(c=gc))if(c=='-')f=-1;
	do a=a*10+c-'0';
	while(isdigit(c=gc));
	a*=f;
}
template<typename T>
void write(T a){
	if(a>=10)write(a/10);
	putchar('0'+a%10);
}

（速度越快，优先级越大，大小显示优先级）

\[scanf < getchar \]

\[printf < puts < putchar \]

其他

• 循环展开
• O2
• 位运算
• 逗号运算符比分号快
• const 标识符
• 少用取模