[Template]高精度模板

[2016-12-9]

重新写一下高精度模板(不要问我为什么)

自认为代码风格比较漂亮(雾

如果有更好的写法欢迎赐教

---

封装结构体big

B是压位用的进制，W是每位长度

size表示长度，d[]就是保存的数字，倒着保存，从1开始

---

[2017-01-14]

update：修改一点bug，并且重载了运算符

[2017-02-16]

update：现在已经觉得这份代码没法看啦.........

[2017-03-25]

update：今天做一道题所以几乎重写了所有高精度...感觉不知道比以前高到哪里去了，以前的代码可能会有bug

这里放现在的代码：

struct Big{
    int a[], n;
    int& operator [](int x) {return a[x];}
    Big():n() {memset(a, , sizeof(a));}
    void ini(int x) {a[]=x; n=;}
};

Big operator *(Big a, int b) {
    int g=;
    for(int i=; i<=a.n; i++)
        g += a[i]*b, a[i] = g%B, g/=B;
    if(g) a[++a.n] = g;
    return a;
}

Big operator *(Big a, Big b) {
    Big c;
    for(int i=; i<=a.n; i++) {
        int g=;
        for(int j=; j<=b.n; j++)
            g += c[i+j-]+a[i]*b[j], c[i+j-] = g%B, g/=B;
        c[i+b.n] = g;
    }
    c.n = a.n + b.n;
    while(c.n> && c[c.n]==) c.n--;
    return c;
}

Big operator +(Big a, Big b) {
    int g=, n=max(a.n, b.n);
    for(int i=; i<=n; i++) {
        g += i<=a.n ? a[i] : ;
        g += i<=b.n ? b[i] : ;
        a[i] = g%B, g/=B;
    }
    a.n = n;
    if(g) a[++a.n] = g;
    return a;
}

Big operator -(Big a, Big b) {
    for(int i=; i<=b.n; i++) {
        if(a[i]<b[i]) a[i]+=B, a[i+]--;
        a[i] -= b[i];
    }
    int p=b.n+;
    while(a[p]<) a[p]+=B, a[++p]--;
    while(a.n> && a[a.n]==) a.n--;
    return a;
}

void Print(Big &a) {
    printf("%d", a[a.n]);
    for(int i=a.n-; i>=; i--) printf("%04d", a[i]);
}

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
const int N=,B=1e4,W=,L=;

struct big{
    int size,d[L];
    big():size(){memset(d,,sizeof(d));}
};

//---------------------------------------------------
bool operator <(big &a,int b){//a<b
    if(a.size==&&a.d[]<b) return true;
    else return false;
}

big operator +(big a,int b){
    int t=a.d[]+b,g=t/B;
    a.d[]=t%B;
    for(int i=;g;i++){//jin wei
        t=a.d[i]+g;
        a.d[i]=t%B;
        g=t/B;
        a.size=max(a.size,i);//update size
    }
    return a;
}
big operator -(big a,int b){
    if(a.d[]<b){//jie wei
        a.d[]+=B;
        int i;
        for(i=;a.d[i]==;i++) a.d[i]+=B-;
        a.d[i]--;
        while(a.d[a.size]==) a.size--;//update size
    }
    a.d[]-=b;//last minus
    return a;
}
big operator *(big a,int b){
    int g=;
    for(int i=;i<=a.size;i++){//mul
        int t=a.d[i]*b+g;
        a.d[i]=t%B;
        g=t/B;
    }
    while(g){//jin wei
        a.d[++a.size]=g%B;//update size
        g/=B;
    }
    return a;
}
big operator /(big a,int b){
    int g=;
    for(int i=a.size;i>=;i--){//divide
        g=g*B+a.d[i];
        a.d[i]=g/b;
        g%=b;
    }
    while(a.d[a.size]==) a.size--;//update size
    return a;
}

//---------------------------------------------------
bool operator <(big a,big b){//a<b
    if(a.size!=b.size) return a.size<b.size;
    for(int i=;i<=a.size;i++)
        if(a.d[i]!=b.d[i]) return a.d[i]<b.d[i];
    return false;//a==b
}
big operator +(big a,big b){
    int g=,i;
    for(i=;;i++){
        if(g==&&i>a.size&&i>b.size) break;
        int t=g;
        t+=i<=a.size?a.d[i]:;
        t+=i<=b.size?b.d[i]:;
        a.d[i]=t%B;
        g=t/B;
    }
    a.size=i-;//update size
    return a;
}
big operator -(big a,big b){
    for(int i=;i<=b.size;i++){
        if(a.d[i]<b.d[i]){//jie wei
            int p=i+;
            while(a.d[p]==) p++;
            a.d[p]--;p--;
            while(p!=i) a.d[p--]+=B-;
            a.d[i]+=B;
        }
        a.d[i]-=b.d[i];
    }
    while(a.d[a.size]==) a.size--;
    if(a.size<=) a.size=;
    return a;
}
big operator *(big a,big b){
    big c;
    for(int i=;i<=a.size;i++){
        int g=;
        for(int j=;j<=b.size;j++){
            c.d[i+j-]+=a.d[i]*b.d[j]+g;
            g=c.d[i+j-]/B;
            c.d[i+j-]%=B;
        }
        c.d[i+b.size]=g;
    }
    c.size=a.size+b.size;
    while(c.d[c.size]==) c.size--;
    if(c.size<=) c.size=;
    return c;
}

//---------------------------------------------------
//压位 B=1e4 W=4
void scan(big &a,char s[]){//annoy B ,if B==10 you can directly use the string
    int len=strlen(s+);
    int p=a.size=len/W+(len%W!=);
    for(int i=;i<=p;i++){
        int r=len-(i-)*W,l=max(len-i*W+,);
        for(int j=l;j<=r;j++) a.d[i]=a.d[i]*+s[j]-'';
    }
}
void print(big &a){//When B==1e4;If B==10 just print
    printf("%d",a.d[a.size]);
    for(int i=a.size-;i>=;i--){
        if(a.d[i]<) printf("");
        else if(a.d[i]<) printf("");
        else if(a.d[i]<) printf("");
        printf("%d",a.d[i]);
    }
    putchar('\n');
}
//不压位 B=10 W=1
//void scan(big &a,char s[]){
//    int len=strlen(s+1);
//    a.size=len;
//    for(int i=1;i<=len;i++) a.d[len-i+1]=s[i]-'0';
//}
//void print(big &a){
//    for(int i=a.size;i>=1;i--) printf("%d",a.d[i]);
//}

//---------------------------------------------------
char s[N];
big a,b;
int main(){
    //freopen("in.txt","r",stdin);
    scanf("%s",s+);scan(a,s);
    scanf("%s",s+);scan(b,s);
    a=a*b;
    print(a);
}
 

以前的代码