题目描述
高精度减法
样例
算法1
C++ 代码
#include <iostream>
#include <vector>
using namespace std;
const int N = 100010;
bool cmp(vector<int> &A, vector<int> &B)
{
if(A.size() != B.size()) return A.size() > B.size();
for(int i = A.size() - 1; i >= 0; i -- )
if(A[i] != B[i])
return A[i] > B[i];
return true;
}
vector<int> sub(vector<int> &A, vector<int> &B)
{
vector<int> C;
int t = 0;
for(int i = 0; i <= A.size(); i ++ )
{
t = A[i] - t;
if(i < B.size()) t -= B[i];
C.push_back((t + 10) % 10);
if(t < 0) t = 1;
else t = 0;
}
while(C.size() > 1 && C.back() == 0) C.pop_back(); //去掉前导0
return C;
}
int main()
{
string a, b;
vector<int> A, B;
cin >> a >> b;
for(int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');
for(int i = b.size() - 1; i >= 0; i -- ) B.push_back(b[i] - '0');
if(cmp(A, B))
{
auto C = sub(A, B);
for(int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);
}
else
{
auto C = sub(B, A);
cout << '-';
for(int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);
}
return 0;
}