[模板] 杂项:二分/离散化/随机数/其他

离散化

int *ptr[nsz],pp=0,inv[nsz],pi=0;
bool cmp(int *a,int *b){return (*a)<(*b);}
void uniq(){
	sort(ptr+1,ptr+pp+1,cmp);
	inv[pi]=-1;
	rep(i,1,pp){
		if((*ptr[i])!=inv[pi])inv[++pi]=ptr[i];
		*ptr[i]=pi;
	}
}

二分

int sol(){
	int l=l0,r=r0,mid,ans=0;
	while(l<=r){
		mid=(l+r)>>1;
		if(jud(mid))ans=mid,r=mid-1;
		else l=mid+1;
	}
	return ans;
}

精确时间

#include<sys/time.h>
	timeval a;
	gettimeofday(&a,0);
	ll t0 = a.tv_sec*1000000+a.tv_usec; //microsecond

随机数

用微秒来设随机数种子.
获取随机数取模即可.
当RAND_MAX较小 (如32768) 时, 可以分别随机高位和低位.

void sr(){
	timeval a;
	gettimeofday(&a,0);
	srand(a.tv_sec*1000000+a.tv_usec);
}
int getr(int l,int r){return rand()%(r-l+1)+l;}
int rand1(int l,int r){return rand()*RAND_MAX+rand();}

指定精度输出

#include<iomanip>

    cout<<fixed<<setprecision(5);
    //cout<<(double)...

取整

#include<cmath>

    floor(v);
    ceil(v);
    round(v);
//using (a-1)/b+1 is wrong when a/b is negative
//neither (a+(b/2))/b
//round(xxx) to avoid '4.99 -> 4'

改变栈大小

# Windows
## the default stack size limit is 2MB

## gcc mingw
### linker commands:
### unit: byte
-Wl,--stack=1024000000

## MSVC
#pragma comment(linker, "/STACK:16777216")

# linux
## show the default stack size limit; which is 8MB
ulimit -s
## set size; unit: KB
ulimit -s 102400
ulimit -s ulimited

## set memory size; unit: KB
ulimit -v 512000