[算法导论]2.1节编程练习C++实现

文章中的伪代码的C++实现：

1.INSERTION-SORT（A）插入排序（非降序排序）

#include <windows.h>
#include <iostream>
#include <vector>
using namespace std;
vector<int> insertion(vector<int>& A){
int length = A.size();
for (int j = 1; j < length; j++){
int key = A[j];
int i = j - 1;
while (i >= 0 && key < A[i]){
A[i + 1] = A[i];
i--;
}
A[i + 1] = key;
}
return A;
}
int main(){
vector<int> A = { 5, 2, 4, 6, 1, 3 };
vector<int> B = insertion(A);
for (int i = 0; i < B.size(); i++){
cout << B[i];
}
cout << endl;
cin.get();
return 0;
}

编程练习的C++实现：

2.1-2 插入排序按照非升序排序，这个实现很简单，只需要将上面1中的代码key<A[i]改为key>A[i]即可。

#include <windows.h>
#include <iostream>
#include <vector>
using namespace std;

vector<int> insertion(vector<int>& A){
int length = A.size();
for (int j = 1; j < length; j++){
int key = A[j];
int i = j - 1;
while (i >= 0 && key > A[i]){
A[i + 1] = A[i];
i--;
}
A[i + 1] = key;
}
return A;
}
int main(){
vector<int> A = { 5, 2, 4, 6, 1, 3 };
vector<int> B = insertion(A);
for (int i = 0; i < B.size(); i++){
cout << B[i];
}
cout << endl;
cin.get();
return 0;
}

2.1-3 顺序查找的简单实现（如果要查找的数不在数组中，返回-1）

 

#include <windows.h>
#include <iostream>
#include <vector>
using namespace std;

int search(vector<int>& A,int v){
int length = A.size();
for (int j=0; j < length; j++)
if (A[j] == v)
return j;
return -1;
}
int main(){
vector<int> A = { 5, 2, 4, 6, 1, 3 };
cout << search(A, 7) << endl;
cin.get();
return 0;
}

2.1-4 实现二进制加法，输入为两歌表示二进制数的数组，输出为一个表示二进制数的数组。

#include <windows.h>
#include <iostream>
#include <vector>
using namespace std;

vector<int> plusAB(vector<int>& A, vector<int>& B){
int len = A.size();
vector<int> C(len + 1);
int tem = 0;
for (int i = len; i >0; i--){
C[i] = A[i - 1] + B[i - 1] + tem;
if (C[i] > 1){
C[i] = C[i] - 2;
tem = 1;
}
else
tem = 0;
}
C[0] = tem;
return C;
}
int main(){
vector<int> A = { 0, 1, 0 };
vector<int> B = { 0, 1, 1 };
vector<int> C(A.size()+1);
C = plusAB(A, B);
for (int i = 0; i < C.size(); i++){
cout << C[i];
}
cout << endl;
cin.get();
return 0;
}