https://ac.nowcoder.com/acm/contest/327/C
C++版本一
#include<bits/stdc++.h>
using namespace std;
int main(){
long double n;
cin>>n;
long double a=1,b=1;
int ans=1;
while(b<n){
a*=3;
b+=a;
ans++;
}
cout<<ans;
return 0;
} C++版本二
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
int lt, la, ln;
void cheng(int *t)
{
int s[1005];
memset(s, 0 , sizeof(s));
for(int i=0; i<lt; i++)
{
s[i] += t[i] * 3;
s[i+1] += s[i]/10;
s[i] %= 10;
}
lt++;
while(s[lt-1]==0 && lt>1)
{
lt--;
}
for(int i=lt-1; i>=0; i--)
{
t[i] = s[i];
}
}
void jia(int *a, int *b)
{
int s[1005];
memset(s, 0 , sizeof(s));
int len = max(la, lt);
for(int i=0; i < len; i++)
{
s[i] += a[i]+b[i];
s[i+1] += s[i]/10;
s[i] %= 10;
}
if(s[len]!=0)
{
len++;
}
la = len;
for(int i=len-1; i>=0;i--)
{
a[i] = s[i];
}
}
bool cmp(int a[], int b[])
{
if(la < ln) return true;
else if(la > ln) return false;
for(int i=la-1; i >= 0; i--)
{
if(a[i] < b[i]) return true;
else if(a[i] > b[i]) return false;
}
return false;
}
char str[1005];
int ans, t[1005], sum[1005], n[1005];
int main()
{
scanf("%s", str);
ln = strlen(str);
for(int i=0; i<=ln-1; i++) n[i] = str[ln-i-1] - '0';
t[0] = 1; lt = 1;
while(cmp(sum, n))
{
jia(sum, t);
ans++;
cheng(t);
}
printf("%d\n", ans);
return 0;
} C++版本三
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF=0x3f3f3f3f;
const ll LLINF=0x3f3f3f3f3f3f3f3f;
const double PI=acos(-1.0);
const double eps=1e-6;
const int MAX=2e5+10;
const ll mod=1e9+7;
const int DIGIT=9;
const int DEPTH=1000000000;
const int MAXN=2020;
typedef ll bignum_t[MAXN+1];
ll read(bignum_t a,istream&is=cin)
{
char buf[MAXN*DIGIT+1],ch;
ll i,j;
memset((void*)a,0,sizeof(bignum_t));
if(!(is>>buf))return 0;
for(a[0]=strlen(buf),i=a[0]/2-1;i>=0;i--)
ch=buf[i],buf[i]=buf[a[0]-1-i],buf[a[0]-1-i]=ch;
for(a[0]=(a[0]+DIGIT-1)/DIGIT,j=strlen(buf);j<a[0]*DIGIT;buf[j++]='0');
for(i=1;i<=a[0];i++)
for(a[i]=0,j=0;j<DIGIT;j++)
a[i]=a[i]*10+buf[i*DIGIT-1-j]-'0';
for(;!a[a[0]]&&a[0]>1;a[0]--);
return 1;
}
void write(const bignum_t a,ostream&os=cout)
{
ll i,j ;
for(os<<a[i=a[0]],i--;i;i--)
os<<setw(DIGIT)<<setfill('0')<<a[i];
}
ll comp(const bignum_t a,const bignum_t b)
{
ll i ;
if(a[0]!=b[0]) return a[0]-b[0];
for(i=a[0];i;i--)
if(a[i]!=b[i])
return a[i]-b[i];
return 0 ;
}
ll comp(const bignum_t a,const ll b)
{
ll c[12]={1};
for(c[1]=b;c[c[0]]>=DEPTH;c[c[0]+1]=c[c[0]]/DEPTH,c[c[0]]%=DEPTH,c[0]++);
return comp(a,c);
}
ll comp(const bignum_t a,const ll c,const ll d,const bignum_t b)
{
ll i,t=0,O=-DEPTH*2;
if(b[0]-a[0]<d&&c)
return 1 ;
for(i=b[0];i>d;i--)
{
t=t*DEPTH+a[i-d]*c-b[i];
if(t>0)return 1;
if(t<O)return 0;
}
for(i=d;i;i--)
{
t=t*DEPTH-b[i];
if(t>0)return 1;
if(t<O)return 0;
}
return t>0 ;
}
void add(bignum_t a,const bignum_t b)
{
ll i ;
for(i=1;i<=b[0];i++)
if((a[i]+=b[i])>=DEPTH)
a[i]-=DEPTH,a[i+1]++;
if(b[0]>=a[0])
a[0]=b[0];
else
for(;a[i]>=DEPTH&&i<a[0];a[i]-=DEPTH,i++,a[i]++);
a[0]+=(a[a[0]+1]>0);
}
void add(bignum_t a,const ll b)
{
ll i=1;
for(a[1]+=b;a[i]>=DEPTH&&i<a[0];a[i+1]+=a[i]/DEPTH,a[i]%=DEPTH,i++);
for(;a[a[0]]>=DEPTH;a[a[0]+1]=a[a[0]]/DEPTH,a[a[0]]%=DEPTH,a[0]++);
}
void sub(bignum_t a,const bignum_t b)
{
ll i;
for(i=1;i<=b[0];i++)
if((a[i]-=b[i])<0)
a[i+1]--,a[i]+=DEPTH;
for(;a[i]<0;a[i]+=DEPTH,i++,a[i]--);
for(;!a[a[0]]&&a[0]>1;a[0]--);
}
void sub(bignum_t a,const ll b)
{
ll i=1;
for(a[1]-=b;a[i]<0;a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH,i++);
for(;!a[a[0]]&&a[0]>1;a[0]--);
}
void sub(bignum_t a,const bignum_t b,const ll c,const ll d)
{
ll i,O=b[0]+d;
for(i=1+d;i<=O;i++)
if((a[i]-=b[i-d]*c)<0)
a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH ;
for(;a[i]<0;a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH,i++);
for(;!a[a[0]]&&a[0]>1;a[0]--);
}
void mul(bignum_t c,const bignum_t a,const bignum_t b)
{
ll i,j;
memset((void*)c,0,sizeof(bignum_t));
for(c[0]=a[0]+b[0]-1,i=1;i<=a[0];i++)
for(j=1;j<=b[0];j++)
if((c[i+j-1]+=a[i]*b[j])>=DEPTH)
c[i+j]+=c[i+j-1]/DEPTH,c[i+j-1]%=DEPTH;
for(c[0]+=(c[c[0]+1]>0);!c[c[0]]&&c[0]>1;c[0]--);
}
void mul(bignum_t a,const ll b)
{
ll i;
for(a[1]*=b,i=2;i<=a[0];i++)
{
a[i]*=b ;
if(a[i-1]>=DEPTH)
a[i]+=a[i-1]/DEPTH,a[i-1]%=DEPTH;
}
for(;a[a[0]]>=DEPTH;a[a[0]+1]=a[a[0]]/DEPTH,a[a[0]]%=DEPTH,a[0]++);
for(;!a[a[0]]&&a[0]>1;a[0]--);
}
void mul(bignum_t b,const bignum_t a,const ll c,const ll d)
{
ll i;
memset((void*)b,0,sizeof(bignum_t));
for(b[0]=a[0]+d,i=d+1;i<=b[0];i++)
if((b[i]+=a[i-d]*c)>=DEPTH)
b[i+1]+=b[i]/DEPTH,b[i]%=DEPTH ;
for(;b[b[0]+1];b[0]++,b[b[0]+1]=b[b[0]]/DEPTH,b[b[0]]%=DEPTH);
for(;!b[b[0]]&&b[0]>1;b[0]--);
}
void div(bignum_t c,bignum_t a,const bignum_t b)
{
ll h,l,m,i;
memset((void*)c,0,sizeof(bignum_t));
c[0]=(b[0]<a[0]+1)?(a[0]-b[0]+2):1 ;
for(i=c[0];i;sub(a,b,c[i]=m,i-1),i--)
for(h=DEPTH-1,l=0,m=(h+l+1)>>1;h>l;m=(h+l+1)>>1)
if(comp(b,m,i-1,a))h=m-1;
else l=m;
for(;!c[c[0]]&&c[0]>1;c[0]--);
c[0]=c[0]>1?c[0]:1;
}
void div(bignum_t a,const ll b,ll&c)
{
ll i;
for(c=0,i=a[0];i;c=c*DEPTH+a[i],a[i]=c/b,c%=b,i--);
for(;!a[a[0]]&&a[0]>1;a[0]--);
}
void sqrt(bignum_t b,bignum_t a)
{
ll h,l,m,i;
memset((void*)b,0,sizeof(bignum_t));
for(i=b[0]=(a[0]+1)>>1;i;sub(a,b,m,i-1),b[i]+=m,i--)
for(h=DEPTH-1,l=0,b[i]=m=(h+l+1)>>1;h>l;b[i]=m=(h+l+1)>>1)
if(comp(b,m,i-1,a))h=m-1;
else l=m;
for(;!b[b[0]]&&b[0]>1;b[0]--);
for(i=1;i<=b[0];b[i++]>>=1);
}
ll length(const bignum_t a)
{
ll t,ret;
for(ret=(a[0]-1)*DIGIT,t=a[a[0]];t;t/=10,ret++);
return ret>0?ret:1;
}
ll digit(const bignum_t a,const ll b)
{
ll i,ret;
for(ret=a[(b-1)/DIGIT+1],i=(b-1)%DIGIT;i;ret/=10,i--);
return ret%10;
}
ll zeronum(const bignum_t a)
{
ll ret,t;
for(ret=0;!a[ret+1];ret++);
for(t=a[ret+1],ret*=DIGIT;!(t%10);t/=10,ret++);
return ret;
}
void comp(ll*a,const ll l,const ll h,const ll d)
{
ll i,j,t;
for(i=l;i<=h;i++)
for(t=i,j=2;t>1;j++)
while(!(t%j))
a[j]+=d,t/=j;
}
void convert(ll*a,const ll h,bignum_t b)
{
ll i,j,t=1;
memset(b,0,sizeof(bignum_t));
for(b[0]=b[1]=1,i=2;i<=h;i++)
if(a[i])
for(j=a[i];j;t*=i,j--)
if(t*i>DEPTH)
mul(b,t),t=1;
mul(b,t);
}
#define SGN(x) ((x)>0?1:((x)<0?-1:0))
#define ABS(x) ((x)>0?(x):-(x))
ll read(bignum_t a,ll&sgn,istream&is=cin)
{
char str[MAXN*DIGIT+2],ch,*buf;
ll i,j;
memset((void*)a,0,sizeof(bignum_t));
if(!(is>>str))return 0;
buf=str,sgn=1;
if(*buf=='-')sgn=-1,buf++;
for(a[0]=strlen(buf),i=a[0]/2-1;i>=0;i--)
ch=buf[i],buf[i]=buf[a[0]-1-i],buf[a[0]-1-i]=ch ;
for(a[0]=(a[0]+DIGIT-1)/DIGIT,j=strlen(buf);j<a[0]*DIGIT;buf[j++]='0');
for(i=1;i<=a[0];i++)
for(a[i]=0,j=0;j<DIGIT;j++)
a[i]=a[i]*10+buf[i*DIGIT-1-j]-'0';
for(;!a[a[0]]&&a[0]>1;a[0]--);
if(a[0]==1&&!a[1])sgn=0;
return 1;
}
struct bigint
{
bignum_t num;
ll sgn;
bigint(ll v){*this=v;}
inline bigint()
{
memset(num,0,sizeof(bignum_t));
num[0]=1;
sgn=0;
}
inline ll operator!()
{
return num[0]==1&&!num[1];
}
inline bigint&operator=(const bigint&a)
{
memcpy(num,a.num,sizeof(bignum_t));
sgn=a.sgn;
return*this;
}
inline bigint&operator=(const ll a)
{
memset(num,0,sizeof(bignum_t));
num[0]=1;
sgn=SGN (a);
add(num,sgn*a);
return*this;
}
inline bigint&operator+=(const bigint&a)
{
if(sgn==a.sgn)add(num,a.num);
else if(sgn&&a.sgn)
{
ll ret=comp(num,a.num);
if(ret>0)sub(num,a.num);
else if(ret<0)
{
bignum_t t;
memcpy(t,num,sizeof(bignum_t));
memcpy(num,a.num,sizeof(bignum_t));
sub (num,t);
sgn=a.sgn;
}
else memset(num,0,sizeof(bignum_t)),num[0]=1,sgn=0;
}
else if(!sgn) memcpy(num,a.num,sizeof(bignum_t)),sgn=a.sgn;
return*this;
}
inline bigint&operator+=(const ll a)
{
if(sgn*a>0)add(num,ABS(a));
else if(sgn&&a)
{
ll ret=comp(num,ABS(a));
if(ret>0)sub(num,ABS(a));
else if(ret<0)
{
bignum_t t;
memcpy(t,num,sizeof(bignum_t));
memset(num,0,sizeof(bignum_t));
num[0]=1;
add(num,ABS (a));
sgn=-sgn;
sub(num,t);
}
else memset(num,0,sizeof(bignum_t)),num[0]=1,sgn=0 ;
}
else if(!sgn) sgn=SGN(a),add(num,ABS(a));
return*this;
}
inline bigint operator+(const bigint&a)
{
bigint ret;
memcpy(ret.num,num,sizeof(bignum_t));
ret.sgn=sgn;
ret+=a;
return ret;
}
inline bigint operator+(const ll a)
{
bigint ret;
memcpy(ret.num,num,sizeof (bignum_t));
ret.sgn=sgn;
ret+=a;
return ret;
}
inline bigint&operator-=(const bigint&a)
{
if(sgn*a.sgn<0)add(num,a.num);
else if(sgn&&a.sgn)
{
ll ret=comp(num,a.num);
if(ret>0)sub(num,a.num);
else if(ret<0)
{
bignum_t t;
memcpy(t,num,sizeof(bignum_t));
memcpy(num,a.num,sizeof(bignum_t));
sub(num,t);
sgn=-sgn;
}
else memset(num,0,sizeof(bignum_t)),num[0]=1,sgn=0;
}
else if(!sgn)add(num,a.num),sgn=-a.sgn ;
return*this ;
}
inline bigint&operator-=(const ll a)
{
if(sgn*a<0)add(num,ABS(a));
else if(sgn&&a)
{
ll ret=comp(num,ABS(a));
if(ret>0)sub(num,ABS(a));
else if(ret<0)
{
bignum_t t;
memcpy(t,num,sizeof(bignum_t));
memset(num,0,sizeof(bignum_t));
num[0]=1;
add(num,ABS(a));
sub(num,t);
sgn=-sgn;
}
else memset(num,0,sizeof(bignum_t)),num[0]=1,sgn=0;
}
else if(!sgn)sgn=-SGN(a),add(num,ABS(a));
return*this ;
}
inline bigint operator-(const bigint&a)
{
bigint ret;
memcpy(ret.num,num,sizeof(bignum_t));
ret.sgn=sgn;
ret-=a;
return ret;
}
inline bigint operator-(const ll a)
{
bigint ret;
memcpy(ret.num,num,sizeof(bignum_t));
ret.sgn=sgn;
ret-=a;
return ret;
}
inline bigint&operator*=(const bigint&a)
{
bignum_t t;
mul(t,num,a.num);
memcpy(num,t,sizeof(bignum_t));
sgn*=a.sgn;
return*this;
}
inline bigint&operator*=(const ll a)
{
mul(num,ABS(a));
sgn*=SGN(a);
return*this;
}
inline bigint operator*(const bigint&a)
{
bigint ret;
mul(ret.num,num,a.num);
ret.sgn=sgn*a.sgn ;
return ret;
}
inline bigint operator*(const ll a)
{
bigint ret;
memcpy(ret.num,num,sizeof(bignum_t));
mul(ret.num,ABS(a));
ret.sgn=sgn*SGN(a);
return ret;
}
inline bigint&operator/=(const bigint&a)
{
bignum_t t;
div(t,num,a.num);
memcpy (num,t,sizeof(bignum_t));
sgn=(num[0]==1&&!num[1])?0:sgn*a.sgn ;
return*this;
}
inline bigint&operator/=(const ll a)
{
ll t;
div(num,ABS(a),t);
sgn=(num[0]==1&&!num [1])?0:sgn*SGN(a);
return*this;
}
inline bigint operator/(const bigint&a)
{
bigint ret;
bignum_t t;
memcpy(t,num,sizeof(bignum_t));
div(ret.num,t,a.num);
ret.sgn=(ret.num[0]==1&&!ret.num[1])?0:sgn*a.sgn ;
return ret;
}
inline bigint operator/(const ll a)
{
bigint ret;
ll t;
memcpy(ret.num,num,sizeof(bignum_t));
div(ret.num,ABS(a),t);
ret.sgn=(ret.num[0]==1&&!ret.num[1])?0:sgn*SGN(a);
return ret;
}
inline bigint&operator%=(const bigint&a)
{
bignum_t t;
div(t,num,a.num);
if(num[0]==1&&!num[1])sgn=0;
return*this;
}
inline ll operator%=(const ll a)
{
ll t;
div(num,ABS(a),t);
memset(num,0,sizeof(bignum_t));
num[0]=1;
add(num,t);
return t;
}
inline bigint operator%(const bigint&a)
{
bigint ret;
bignum_t t;
memcpy(ret.num,num,sizeof(bignum_t));
div(t,ret.num,a.num);
ret.sgn=(ret.num[0]==1&&!ret.num [1])?0:sgn;
return ret;
}
inline ll operator%(const ll a)
{
bigint ret;
ll t;
memcpy(ret.num,num,sizeof(bignum_t));
div(ret.num,ABS(a),t);
memset(ret.num,0,sizeof(bignum_t));
ret.num[0]=1;
add(ret.num,t);
return t;
}
inline bigint&operator++()
{
*this+=1;
return*this;
}
inline bigint&operator--()
{
*this-=1;
return*this;
}
inline ll operator>(const bigint&a)
{
return sgn>0?(a.sgn>0?comp(num,a.num)>0:1):(sgn<0?(a.sgn<0?comp(num,a.num)<0:0):a.sgn<0);
}
inline ll operator>(const ll a)
{
return sgn>0?(a>0?comp(num,a)>0:1):(sgn<0?(a<0?comp(num,-a)<0:0):a<0);
}
inline ll operator>=(const bigint&a)
{
return sgn>0?(a.sgn>0?comp(num,a.num)>=0:1):(sgn<0?(a.sgn<0?comp(num,a.num)<=0:0):a.sgn<=0);
}
inline ll operator>=(const ll a)
{
return sgn>0?(a>0?comp(num,a)>=0:1):(sgn<0?(a<0?comp(num,-a)<=0:0):a<=0);
}
inline ll operator<(const bigint&a)
{
return sgn<0?(a.sgn<0?comp(num,a.num)>0:1):(sgn>0?(a.sgn>0?comp(num,a.num)<0:0):a.sgn>0);
}
inline ll operator<(const ll a)
{
return sgn<0?(a<0?comp(num,-a)>0:1):(sgn>0?(a>0?comp(num,a)<0:0):a>0);
}
inline ll operator<=(const bigint&a)
{
return sgn<0?(a.sgn<0?comp(num,a.num)>=0:1):(sgn>0?(a.sgn>0?comp(num,a.num)<=0:0):a.sgn>=0);
}
inline ll operator<=(const ll a)
{
return sgn<0?(a<0?comp(num,-a)>=0:1):(sgn>0?(a>0?comp(num,a)<=0:0):a>=0);
}
inline ll operator==(const bigint&a)
{
return(sgn==a.sgn)?!comp(num,a.num):0;
}
inline ll operator==(const ll a)
{
return(sgn*a>=0)?!comp(num,ABS(a)):0;
}
inline ll operator!=(const bigint&a)
{
return(sgn==a.sgn)?comp(num,a.num):1 ;
}
inline ll operator!=(const ll a)
{
return(sgn*a>=0)?comp(num,ABS(a)):1 ;
}
inline ll operator[](const ll a)
{
return digit(num,a);
}
friend inline istream&operator>>(istream&is,bigint&a)
{
read(a.num,a.sgn,is);
return is;
}
friend inline ostream&operator<<(ostream&os,const bigint&a)
{
if(a.sgn<0) os<<'-';
write(a.num,os);
return os;
}
friend inline bigint sqrt(const bigint&a)
{
bigint ret;
bignum_t t;
memcpy(t,a.num,sizeof(bignum_t));
sqrt(ret.num,t);
ret.sgn=ret.num[0]!=1||ret.num[1];
return ret;
}
friend inline bigint sqrt(const bigint&a,bigint&b)
{
bigint ret;
memcpy(b.num,a.num,sizeof(bignum_t));
sqrt(ret.num,b.num);
ret.sgn=ret.num[0]!=1||ret.num[1];
b.sgn=b.num[0]!=1||ret.num[1];
return ret;
}
inline ll length()
{
return :: length(num);
}
inline ll zeronum()
{
return :: zeronum(num);
}
};
bigint gcd(bigint a,bigint b)
{
return b==0?a:gcd(b,a%b);
}
bigint lcm(bigint a,bigint b)
{
return a/gcd(a,b)*b;
}
int main()
{
bigint x=0,s=1,a=1;
cin>>x;
while(s<x){
s*=3;
s+=1;
a+=1;
}
cout<<a<<endl;
return 0;
}
Python版本一
std
题解：数学 高精度
n=int(input())
x=1
s=1
while x<n:
x=3*x+1
s+=1
print(s) JAVA版本一
import java.math.BigDecimal;
import java.util.Scanner;
import java.math.BigInteger;
public class Main {//类必须是Main
public static void main(String args[])
{
Scanner scan = new Scanner(System.in);
BigInteger a;
BigInteger b = new BigInteger("1");
BigInteger chen=new BigInteger("3");
BigInteger jia=new BigInteger("1");
a = scan.nextBigInteger();
int cnt=1;
while(a.compareTo(b)>0)
{
cnt++;
b=b.multiply(chen);
b=b.add(jia);
}
System.out.println(cnt);
return;
}
}
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