✨博主:命运之光 ✨专栏:算法基础学习
前言:算法学习笔记记录日常分享,需要的看哈O(∩_∩)O,感谢大家的支持!
1.大整数存储(用数组存,每一位存一位数字)//从个位数字开始存,最后一位存最高位(方便进行进位等运算)
// C = A + B, A >= 0, B >= 0
vector<int> add(vector<int> &A, vector<int> &B)
{
if (A.size() < B.size()) return add(B, A);
vector<int> C;
int t = 0;
for (int i = 0; i < A.size(); i ++ )
{
t += A[i];
if (i < B.size()) t += B[i];
C.push_back(t % 10);
t /= 10;
}
if (t) C.push_back(t);
return C;
}
// C = A - B, 满足A >= B, A >= 0, B >= 0
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;
else t = 0;
}
while (C.size() > 1 && C.back() == 0) C.pop_back();
return C;
}
// C = A * b, A >= 0, b >= 0
vector<int> mul(vector<int> &A, int b)
{
vector<int> C;
int t = 0;
for (int i = 0; i < A.size() || t; i ++ )
{
if (i < A.size()) t += A[i] * b;
C.push_back(t % 10);
t /= 10;
}
while (C.size() > 1 && C.back() == 0) C.pop_back();
return C;
}
// A / b = C ... r, A >= 0, b > 0
vector<int> div(vector<int> &A, int b, int &r)
{
vector<int> C;
r = 0;
for (int i = A.size() - 1; i >= 0; i -- )
{
r = r * 10 + A[i];
C.push_back(r / b);
r %= b;
}
reverse(C.begin(), C.end());
while (C.size() > 1 && C.back() == 0) C.pop_back();
return C;
}
#include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
vector<int> add(vector<int> a,vector<int> b){
vector<int> res;
int t=0;
for(int i=0;i<a.size()||i<b.size();i++){
if(i<a.size())
t+=a[i];
if(i<b.size())
t+=b[i];
res.push_back(t%10);
t=t/10;
}
if(t)
res.push_back(1);
return res;
}
int main(){
string s1,s2;
cin>>s1>>s2;
vector<int> a,b;
for(int i=s1.length()-1;i>=0;i--)
a.push_back(s1[i]-'0');
for(int i=s2.length()-1;i>=0;i--)
b.push_back(s2[i]-'0');
vector<int> ans=add(a,b);
for(int i=ans.size()-1;i<0;i++)
cout<<ans[i];
}
#include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
bool compare(const vector<int> &a,const vector<int> &b){//a比b大时返回true
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> res;
int t=0;
for(int i=0;i<a.size();i++){
t=a[i]-t;
if(i<b.size())
t-=b[i];
res.push_back((10+t)%10);
if(t<0)
t=1;
else
t=0;
}
while(res.size()>1&&res.back()==0)
res.pop_back();
return res;
}
int main(){
string s1,s2;
cin>>s1>>s2;
vector<int> a,b;
for(int i=s1.length()-1;i>=0;i--)
a.push_back(s1[i]-'0');
for(int i=s2.length()-1;i>=0;i--)
b.push_back(s2[i]-'0');
vector<int> ans;
if(compare(a,b)){
ans=sub(a,b);
}
else{
ans=sub(b,a);
printf("-");
}
for(int i=ans.size()-1;i>=0;i--){
cout<<ans[i];
}
return 0;
}
#include <iostream>
#include <string>
#include <vector>
#include <cstdio>
#include <algorithm>
using namespace std;
vector<int> mul(vector<int> A,int b){
int t=0;
vector<int> C;
for(int i=0;i<A.size();i++){
t+=A[i]*b;
C.push_back(t%10);
t=t/10;
}
while(t){
C.push_back(t%10);
t=t/10;
}
return C;
}
int main(){
vector<int> A;
int b;
string s;
cin>>s>>b;
for(int i=s.length()-1;i>=0;i--){
A.push_back(s[i]-'0');
}
vector<int> ans=mul(A,b);
for(int i=ans.size()-1;i>=0;i--){
cout<<ans[i];
}
}
#include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
vector<int> div(vector<int> A,int b,int &r){
vector<int> C;
r=0;
//除法是从最高位开始做除
for(int i=A.size()-1;i>=0;i--){
r=r*10+A[i];
C.push_back(r/b);
r=r%b;
}
while(C.size()>1&&C.front()==0)
C.erase(C.begin());
return C;
}
int main(){
vector<int> A;
int b,r;
string s;
cin>>s>>b;
for(int i=s.length()-1;i>=0;i--){
A.push_back(s[i]-'0');
}
vector<int> ans=div(A,b,r);
for(int i=0;i<=ans.size()-1;i++){
cout<<ans[i];
}
if(r!=0){
cout<<endl;
cout<<"有余数:"<<r<<endl;
}
}