#include <iostream> #include <algorithm> #include <string> using namespace std; string num1, num2; int a1[10005], a2[10005], len1, len2; bool sgn; bool cmp(string a, string b){ if(a.size() != b.size()) { return a.size() < b.size(); } return a < b; } int main() { freopen("subtraction.in","r",stdin); freopen("subtraction.out","w",stdout); cin >> num1 >> num2; if(cmp(num1,num2)){ sgn = true; swap(num1,num2); } len1 = num1.size(); for (int i = 0; i < len1; i++) { a1[i] = num1[len1 - 1 - i] - '0'; } len2 = num2.size(); for (int i = 0; i < len2; i++) { a2[i] = num2[len2 - 1 - i] - '0'; } for (int i = 0; i < len1; i ++){ a1[i] -= a2[i]; } for (int i = 0; i < len1; i ++){ while(a1[i] < 0){ a1[i + 1] --; a1[i] += 10; } } while(len1 > 1 && a1[len1 - 1] == 0){ len1 --; } if(sgn){ cout << "-"; } for (int i = len1 - 1; i >= 0; i--) { cout << a1[i]; } cout << endl; return 0;

较简单的高精度题，但要判断大小。

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
int a[100010],b[100010],c[100010];
bool lower(string A,string B){
    if (A.size()<B.size()){
        return true;
    }else{
        return A.size()==B.size()&&A.compare(B)<0;
    }
    return false;
}
int main(){
    freopen("subtraction.in","r",stdin);
    freopen("subtraction.out","w",stdout);
	string A,B;
	cin>>A>>B;
	bool is=0;
	int len=max(A.size(),B.size());
	if (lower(A,B)){
		swap(A,B);
		is=1;
	}
	for (int i=A.size()-1,j=0;i>=0;i--,j++){
		a[j]=A[i]-'0';
	}
	for (int i=B.size()-1,j=0;i>=0;i--,j++){
		b[j]=B[i]-'0';
	}
	
	for (int i=0;i<len;i++){
		c[i]+=a[i]-b[i];
		if (c[i]<0){
			c[i+1]--;
			c[i]+=10;
		}
	}
	for (int i=0;i<100010;i++){
		c[i+1]+=c[i]/10;
		c[i]%=10;
	}
	for (;!c[len-1];){
		len--;
	}
	if (is==1){
		cout<<'-';
	}
	bool r=0;
	for (int i=len-1;i>=0;i--){
		cout<<c[i];
		r=1;
	}
	if (!r) cout<<0; 
	return 0;
}