大整数减法

CODE[VS] 3115 高精度练习之减法

题目链接.

日常水一水，没啥好说的，就是模拟

#include<bits/stdc++.h>
using namespace std;
int main()
{
	char zf='?';
	string a,b;
	vector <int> c,d;
	int cc[505]={0},dd[505]={0},ans[505]={0};
	cin>>a>>b;
	
		if(a.length()>b.length()) zf='+';
		else if(a.length()<b.length())zf='-';
		else {
			for(int i=0;i<a.length();i++)
			{
				if(a[i]>b[i]){
					zf='+';
					break;
				}else if(a[i]<b[i]){
					zf='-';
					break;
				}
			}
		}
	if(zf=='?'){
		printf("0");
		return 0;
	}
	else 
	if(zf=='-')swap(a,b);
//	cout<<a<<endl<<b;
	reverse(a.begin(),a.end());
	reverse(b.begin(),b.end());
	for(int i=0;i<a.length();i++)cc[i]=a[i]-'0';
	for(int i=0;i<b.length();i++)dd[i]=b[i]-'0'; 
	for(int i=0;i<max(a.length(),b.length());i++)ans[i]=cc[i]-dd[i];
	for(int i=0;i<max(a.length(),b.length());i++){
		if(ans[i]<0){
			ans[i]=ans[i]+10;
			ans[i+1]-=1;
		}
	}
	if(zf=='-')printf("-");
	int fei=0;
	for(int i=max(a.length(),b.length())-1;i>=0;i--)
	{
		if(ans[i]==0&&fei==0)continue;
		else fei=1;
		printf("%d",ans[i]);
	}
	//if(ans[max(a.length(),b.length())-1]!=0)printf("%d",ans[max(a.length(),b.length())-1]);
	return 0;
	/*
	reverse(a.begin(),a.end());
	reverse(b.begin(),b.end());
	
	
	int la=a.length(),lb=b.length();
	int len=0,flag=0;
	cout<<a<<' '<<b<<endl;
	for(int i=0;i<max(la,lb);i++)
	{
		if(flag)
		c.insert(c.begin(),a[i]+b[i]-'0'-'0'+1);
		else 
		c.insert(c.begin(),a[i]+b[i]-'0'-'0');
		flag=0;
		if(c[i]>=10)
		{
			c[i]-=10;
			flag=1;
		}
	}
	if(flag)
		c.insert(c.begin(),1);
	for(int i=c.size()-1;i>=0;i--)
	cout<<c[i]<<' ';
//	cout<<a<<endl<<b;
*/	
}