Question

我正在研究 Accelerated C++: Practical Programming by Example ，我被以下问题困住了。

#include <iostream>
#include <vector>
#include <cctype>
#include <algorithm>
using namespace std;


vector<string> split(const string&s){
    vector<string> ret;
    typedef string::size_type string_size;
    string_size i=0;
    while (i!=s.size()){
        while (i!=s.size() && isspace(s[i])){
            i++;
        }
        string_size j=i;
        while (j!=s.size() && !isspace(s[j])){
            j++;
        }
        if (i!=j){
            ret.push_back(s.substr(i,j-i));
            i=j;
        }
    }
    return ret;
}

void Display(vector<string> s){
    for (vector<string>::size_type i=0;i!=s.size();i++){
        cout<<s[i]<<endl;
    }
}

vector<string> Rotation(string&s){
    string ss=s+" "+s;
    vector<string>s1=split(s);
    vector<string>ret;
    ret.push_back(s);
    string::size_type slength=s.size();
    string::size_type count=0;
    for (vector<string>::size_type i=0;i!=s1.size()-1;i++){
        string k=s1[i];
        string::size_type ksize=k.size();
        count+=ksize+1;
        string pushed=ss.substr(count,slength);
        ret.push_back(pushed);
    }
    return ret;
}

string lower(const string&s){
    string ret;
    for(string::size_type i=0;i!=s.size();i++){
        ret.push_back(tolower(s[i]));
    }
    return ret;
}

bool compare(const string& s1, const string& s2){
    return lower(s1)<lower(s2);
}

int main() {
    string s;
    cout<<"Enter String"<<endl;
    vector<string> vs;
    while (getline(cin,s)){
        vector<string>Rotated=Rotation(s);
        vs.insert(vs.end(),Rotated.begin(),Rotated.end());
    }
    sort(vs.begin(),vs.end(),compare);
    Display(vs);
    return 0;
}

我已经完成了第1步和第2步（旋转和排序），但我不知道如何取消旋转。我已经搜索了这个问题一段时间了，有些解决方案说我应该在开始时初始化结构。我想知道我当前的代码是否仍能解决最后一步，或者我需要更改我编码的所有内容。

Answer 1

在思考了一段时间后，我解决了我的这个问题。以下是我的代码。有没有办法改进我的算法，虽然我已经觉得它很好。

#include <iostream>
#include <vector>
#include <cctype>
#include <algorithm>
using namespace std;

struct Input{
    string word;
    int interpoint;
};

vector<string> split(const string&s){
    vector<string> ret;
    typedef string::size_type string_size;
    string_size i=0;
    while (i!=s.size()){
        while (i!=s.size() && isspace(s[i])){
            i++;
        }
        string_size j=i;
        while (j!=s.size() && !isspace(s[j])){
            j++;
        }
        if (i!=j){
            ret.push_back(s.substr(i,j-i));
            i=j;
        }
    }
    return ret;
}

string joinstring(vector<string>&vs){
    string result;
    for (vector<string>::size_type i=0;i!=vs.size();i++){
        if (i==vs.size()-1)
            result+=vs[i];
        else
            result+=vs[i]+" ";
    }
    return result;
}

vector<Input> Rotation(const string& s){
    vector<Input> Rotated;
    vector<string> splited=split(s);
    vector<string>::size_type splitsize=splited.size();
    for (vector<string>::size_type i=0;i!=splitsize;i++){
        Input OneRotated;
        vector<string> splited=split(s);
        rotate(splited.begin(),splited.begin()+i,splited.end());
        OneRotated.interpoint=splitsize-i;
        OneRotated.word=joinstring(splited);
        Rotated.push_back(OneRotated);
    }
    return Rotated;
}


void Display(vector<string> s){
    for (vector<string>::size_type i=0;i!=s.size();i++){
        cout<<s[i]<<endl;
    }
}

string lower(const string&s){
    string ret;
    for(string::size_type i=0;i!=s.size();i++){
        ret.push_back(tolower(s[i]));
    }
    return ret;
}

bool compare(Input& s1, Input& s2){
    return lower(s1.word)<lower(s2.word);
}

vector<string> Unrotate(vector<Input>& Total, vector<string>& Left){
    vector<string>Right;
    for(vector<Input>::size_type i=0;i!=Total.size();i++){
        vector<string>splited=split(Total[i].word);
        int spoint=Total[i].interpoint;
        vector<string>TheLeft(splited.begin()+spoint,splited.end());
        vector<string>TheRight(splited.begin(),splited.begin()+spoint);
        Left.push_back(joinstring(TheLeft));
        Right.push_back(joinstring(TheRight));
    }
    return Right;
}

vector<string> reconstruct(vector<string>&s){
    string::size_type maxlen=0;
    for (vector<string>::size_type i=0;i!=s.size();i++){
        maxlen=max(maxlen,s[i].size());
    }
    vector<string>ret;
    for (vector<string>::size_type j=0;j!=s.size();j++){
        ret.push_back(string(maxlen-s[j].size(),' ')+s[j]);
    }
    return ret;
}


vector<string>hcat(const vector<string>& left, const vector<string>& right)
{
    vector<string> ret;
    vector<string>::size_type i = 0, j = 0;
    while (i != left.size() || j != right.size()) {

        string s;
        // copy a row from the left-hand side, if there is one
        if (i != left.size())
            s = left[i++];


        if (j != right.size())
            s += "  "+right[j++];

        ret.push_back(s);
    }
    return  ret;
}

int main() {
    string s;
    cout << "Enter String" <<endl;
    vector<Input> vs;
    while (getline(cin, s)) {
        vector<Input> Rotated=Rotation(s);
        vs.insert(vs.end(),Rotated.begin(),Rotated.end());
    }
    sort(vs.begin(),vs.end(),compare);
    vector<string> LeftBlock;
    vector<string> RightBlock = Unrotate(vs,LeftBlock);
    Display(hcat(reconstruct(LeftBlock),RightBlock));

    return 0;
}

如何取消旋转置换索引

1 个答案: