高位优先的字符串排序(c++ ASCII)

核心算法
SortString.h

#pragma once
#include <memory>
#include <string>

class SortString
{
private:
    const int R = 256;
    std::string *row;
    int size;
private:
    int toIndex(const std::string& s,const int& pos)
    {
        if (pos <= s.length())
            return s[pos];
        else
            return -1;
    }
public:
    SortString(std::string s[], const int& n)
        :row(s),size(n)
    {

    }
    void sort()
    {
        sort(0, size - 1, 0);
    }
    void sort(const int& lo,const int& hi,int d)
    {
        if (lo >= hi)
            return;
        //可通过一定阈值进行插入排序
        std::unique_ptr<int[]> count(new int[R + 2]);
        std::unique_ptr<std::string[]> aux(new std::string[(hi - lo) + 1]);
        for (int i = 0; i < R + 2; ++i)
            count[i] = 0;
        for (int i = lo; i <= hi; ++i)
            count[toIndex(row[i],d) + 2]++;
        // ASCII 0 -- 255 起始位置对应  count[1] -- count[256]
        // count[0]用于存放超出索引值的起始位置
        for (int i = 0; i < R + 1; ++i)
            count[i + 1] += count[i];
        //将row[lo] -- row[hi] 映射为排序后的 aux[0] -- aux[hi - lo]
        for (int i = lo; i <= hi; ++i)
            aux[count[toIndex(row[i], d) + 1]++] = row[i];
        // 回写
        for (int i = lo; i <= hi; ++i)
            row[i] = aux[i - lo];
        for (int i = 0; i < R; ++i)
            sort(lo + count[i], lo + count[i + 1] - 1, d + 1);
    }
};

测试 main.cpp

#include <iostream>
#include "SortString.h"

using namespace std;

int main()
{
    string s[13] =
    {
        "black",
        "clock",
        "all",
        "angle",
        "demo",
        "girl",
        "fork",
        "emplace",
        "abcde",
        "acdbe",
        "aaba",
        "calo",
        "daole"
    };
    SortString ss(s, 13);
    for (int i = 0; i < 13; ++i)
        cout << s[i] << endl;
    cout << "--------------------" << endl;
    ss.sort();
    for (int i = 0; i < 13; ++i)
        cout << s[i] << endl;
    system("pause");
    return 0;
}