[Template]高精度模板

Posted 2020-08-22 Candy?

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

 

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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

 

 

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#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
const int N=1005,B=1e4,W=4,L=1005;

struct big{
    int size,d[L];
    big():size(0){memset(d,0,sizeof(d));}
};

//---------------------------------------------------
bool cmpInt(big &a,int b){//a>=b
    if(a.size>1) return true;
    else if(a.d[1]>=b) return true;
    return false;
}
void addInt(big &a,int b){
    int t=a.d[1]+b,g=t/B;
    a.d[1]=t%B;
    for(int i=2;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
    }
}
void mnuInt(big &a,int b){
    if(a.d[1]<b){//jie wei
        a.d[1]+=B;
        int i;
        for(i=2;a.d[i]==0;i++) a.d[i]+=B-1;
        a.d[i]--;
        while(a.d[a.size]==0) a.size--;//update size
    }
    a.d[1]-=b;//last minus
}
void mulInt(big &a,int b){
    int g=0;
    for(int i=1;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;
    }
}
void divInt(big &a,int b){
    int g=0;
    for(int i=a.size;i>=1;i--){//divide
        g=g*B+a.d[i];
        a.d[i]=g/b;
        g%=b;
    }
    while(a.d[a.size]==0) a.size--;//update size
}

//---------------------------------------------------
bool cmp(big &a,big &b){//a>b
    if(a.size!=b.size) return a.size>b.size;
    for(int i=1;i<=a.size;i++)
        if(a.d[i]!=b.d[i]) return a.d[i]>b.d[i];
    return false;//a==b
}
void add(big &a,big &b){//a=a+b
    int g=0,i;
    for(i=1;;i++){
        if(g==0&&i>a.size&&i>b.size) break;
        int t=g;
        t+=i<=a.size?a.d[i]:0;
        t+=i<=b.size?b.d[i]:0;
        a.d[i]=t%B;
        g=t/B;
    }
    a.size=i-1;//update size
}
void mnu(big &a,big &b){//a=a-b
    for(int i=1;i<=b.size;i++){
        if(a.d[i]<b.d[i]){
            int p=i+1;
            while(a.d[p]==0) p++;
            a.d[p]--;
            a.d[i]+=B;
        }
        a.d[i]-=b.d[i];
    }
    while(a.d[a.size]==0) a.size--;
}
void mul(big &a,big &b,big &c){//c=a*b
    for(int i=1;i<=a.size;i++){
        int g=0;
        for(int j=1;j<=b.size;j++){
            c.d[i+j-1]+=a.d[i]*b.d[j]+g;
            g=c.d[i+j-1]/B;
            c.d[i+j-1]%=B;
        }
        c.d[i+b.size]=g;
    }
    c.size=a.size+b.size;
    while(c.d[c.size]==0) c.size--;
}

//---------------------------------------------------
void scan(big &a,char s[]){//annoy B ,if B==10 u can directly use the string
    int len=strlen(s+1);
    int p=a.size=len/W+(len%W!=0);
    for(int i=1;i<=p;i++){
        int r=len-(i-1)*W,l=max(len-i*W+1,1);
        for(int j=l;j<=r;j++) a.d[i]=a.d[i]*10+s[j]-‘0‘;
    }
}
void print(big &a){
    printf("%d",a.d[a.size]);
    for(int i=a.size-1;i>=1;i--){
        if(a.d[i]<10) printf("000");
        else if(a.d[i]<100) printf("00");
        else if(a.d[i]<1000) printf("0");
        printf("%d",a.d[i]);
    }
    putchar(‘\n‘);
}

//---------------------------------------------------
int main(){
}