#include"RADIX_SORT_GET_WZ.h"

#pragma once
#include<vector>
#include<algorithm>
#include<string>
#include<sstream>  //stringstream
#include<iomanip> //setw setfill
//内置变量pass-by-value more than pass-by-reference ? 
//P12 --Effective C++(Chinese)

//d位数，A数字
int get_d(const std::vector<int>& A)
{
    int max = *std::max_element(A.cbegin(), A.cend());
    int d = 0;
    for (int i = max; i != 0;d++)
    {
        i /= 10;
    }
    return d;
}

int get_ws(const std::vector<int>& A, int j,int ws)
{
    int d = get_d(A);
    auto s = std::to_string(A[j]);
    std::stringstream ss;
    ss << std::left << std::setfill('0') << std::setw(d + 1) << s;
    s = ss.str();
    ss << std::right << std::setfill(' ');
    int k = s[ws] - '0';
    return k;
}
//k:A数组中最大值，ws： 对A的的第几位排序 A[ws]
void Count_sort_wz(std::vector<int>& A, int ws)
{
//    ws = pow(10, ws);
    std::vector<int> c(10);
    for (int j = 0;j != A.size();++j)
        ++c[get_ws(A,j,ws)];
    for (int i = 1;i <= 10;++i)
        c[i] += c[i - 1];
    std::vector<int> b(A.size());
    for (int i = A.size() - 1;i >= 0;--i)
        b[--c[get_ws(A,i,ws)]] = A[i];
    for (int i = 0; i != A.size();++i)
        A[i] = b[i];
}


void Radix_Sort(std::vector<int>& A)
{
    int max = *std::max_element(A.cbegin(), A.cend());
    int d = get_d(A);
    for (int ws = 0;ws != d; ++ws)
    {
        //max 这时为0
        Count_sort_wz(A, ws);
    }
}

参考

int转成string的同时加上前缀0

convert char to int