高精

今天模拟

考了一堆高精题

看到题目的一瞬间：awsl 物理意义上的

qaqqqqaqaqaqaqaqaqaqqq

然后强行刚题

首先是高精度加法

要先把短的补位0

然后。。没了

#include<cstdio>
#include<iostream>
#define sev en
using namespace std;

string s,t;

string add(string str1,string str2) {
    string str;
    int len1 = str1.length();
    int len2 = str2.length();
    if(len1 < len2) {
        for(int i = 1; i <= len2-len1; i++)
            str1 = "0" + str1;
    } else {
        for(int i = 1; i <= len1 - len2; i++)
            str2 = "0" + str2;
    }
    len1 = str1.length();
    int cf = 0;
    int temp;
    for(int i = len1 - 1; i >= 0; i--) {
        temp = str1[i] - '0' + str2[i] - '0' + cf;
        cf=temp / 10;
        temp %= 10;
        str = char(temp + '0') + str;
    }
    if(cf != 0)  
        str = char(cf + '0') + str;
    return str;
}

int main() {
    cin >> s >> t;
    cout << add(s,t);
    return 0;
}    

然后是高精度减法

先判断一下先输的数小还是后输的数小

提前输出负号

再用大的减小的

最后别忘了清空前导零

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define sev en
using namespace std; 
const int maxn = 10010; 

int len1, len2; 
int a[maxn], b[maxn]; 
string s1, s2;

bool compare(string a, string b){
    if (a.size() < b.size()) return true;  
    if (a.size() > b.size()) return false;
    for (int i = 0; i < a.size(); ++i){
        if (a[i] > b[i]) return false;    
        if (b[i] > a[i]) return true; 
    }
    return false;
}

int main(){
    cin >> s1;         
    cin >> s2; 
    if (compare(s1, s2)){
        swap(s1, s2);  
        printf("-"); 
    }
    len1 = s1.size(); 
    len2 = s2.size(); 
    for (int i = 0; i < len1; ++i) a[len1 - i] = s1[i] - '0'; 
    for (int i = 0; i < len2; ++i) b[len2 - i] = s2[i] - '0'; 
    for (int i = 1; i <= len1; ++i){
        a[i] -= b[i];            
        if (a[i] < 0){                           
            a[i + 1]--;            
            a[i] += 10; 
        }
    }
    while (a[len1] == 0 && len1 > 1) len1--; 
    for (int i = len1; i >= 1; --i)          
      printf("%d", a[i]); 
    return 0; 
}

然后是高精乘

记忆犹新，NOIP前考了一次，写跪了

是学长帮忙改的。。。整个改掉了emmmm

这次重写心理阴影巨大

写了好久www

但挺简单的。。。没啥可说

#include<cstdio>
#include<cstring>
#define sev en
using namespace std;
#define N 100010

char x[N],y[N];
int a[N],b[N],c[N << 1];

int main() {
//    freopen("t.in","r",stdin);
//    freopen("t.out","w",stdout);
    scanf("%s",x);
    scanf("%s",y);
    a[0] = strlen(x),b[0] = strlen(y);
    for(int i = 1; i <= a[0]; i++)
        a[i] = x[a[0] - i] - '0';
    for(int i = 1; i <= b[0]; i++)
        b[i] = y[b[0] - i] - '0';
    for(int i = 1; i <= a[0]; i++)
        for(int j = 1; j <= b[0]; j++)
            c[i + j - 1] += a[i] * b[j];
    int len = a[0] + b[0];
    for(int i = 1; i <= len; i++)
        if(c[i] > 9) {
            c[i + 1] += c[i] / 10;
            c[i] %= 10;
        }
    while(c[len] == 0 && len > 1)
        len--;
    for(int i = len; i >= 1; i--)
        printf("%d",c[i]);
    return 0;
}

最后还有个阶乘

代码没有

等我到时候找找看吧www