C算法模板->大数减法
作者:互联网
#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <map>
using namespace std;
bool cmp(vector<int>& A, vector<int>& B) //判断是否A >= 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 1;
}
vector<int> sub(vector<int>& A, vector<int>& B)
{
vector<int> C;
for (int i = 0, t = 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;//判断是否退位
else t = 0;
}
while (C.size() > 1 && C.back() == 0) //去掉前导0
C.pop_back();
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);
printf("-");
for (int i = C.size() - 1; i >= 0; i--) printf("%d", C[i]);
}
return 0;
}
总体思路
- cmp函数判断 A >= B
- 根据A B 的大小来分情况输出答案的正负
- 退位时 t == 1
some details
标签:return,大数,int,--,vector,减法,include,模板,size 来源: https://blog.csdn.net/GuLeng______/article/details/122384509