信息论与编码上机

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mb640163eb338d0 2023-03-03 13:47:06 博主文章分类：各种课设 ©著作权

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香农：

#include <stdio.h>
#include <iostream>
#include <string.h>
#include <algorithm>
#include <bitset>
#include <math.h>
#include <ctype.h>
#include <time.h>
#include <queue>
#include <map>
#include <set>

using namespace std;

const int MAXN = 11000;

double p[MAXN], sump[MAXN], li[MAXN];
int n, LI[MAXN];
char code[MAXN][100];
bool cmp(double a, double b)
{
    return a > b;
}
void init()
{
    cout << "请依次输入信源符号的概率：";
    memset(p, 0, sizeof(p));
    memset(sump, 0, sizeof(sump));
    for (int i = 1; i <= n; i++)
        cin >> p[i];
    sort(p + 1, p + 1 + n, cmp);
    for (int i = 2; i <= n; i++)
        sump[i] = sump[i - 1] + p[i - 1];
}

void solve()
{
    for (int i = 1; i <= n; i++)
    {
        li[i] = (-1)*(log10(p[i]) / log10(2));
        LI[i] = ceil(li[i]);
    }

    for (int i = 1; i <= n; i++)
    {
        for (int j = 0; j < LI[i]; j++)
        {
            sump[i] *= 2;

            if (sump[i] - 1 >= 0)
            {
                code[i][j] = '1';
                sump[i] -= 1;
            }
            else
                code[i][j] = '0';
        }
    }
    cout << "编码为：" << endl;
    for (int i = 1; i <= n; i++)
        cout << code[i] << " ";
    cout << endl;
}

int main()
{
    cout << "请输入信源符号个数n：";
    cin >> n;
    {
        init();
        solve();
    }
    return 0;
}
/*
测试数据：
7
0.20 0.19 0.18 0.17 015 0.10 0.01
*/

费诺：

#include <stdio.h>
#include <iostream>
#include <string.h>
#include <algorithm>
#include <bitset>
#include <math.h>
#include <ctype.h>
#include <time.h>
#include <queue>
#include <map>
#include <set>
#include <iomanip>

using namespace std;

int n;
double p[10000];
string *code;

void fano(int a, int b)     
{
    if ((b - a) >= 1)       
    {
        double sum = 0;
        for (int i = a; i <= b; i++)
            sum += p[i];
        double s1 = 0, *s = new double[10];
        for (int i = a; i <= b; i++)
        {
            s1 += p[i]; s[i] = fabs(2 * s1 - sum) / sum;
        }
        double min = s[a];  int c;
        for (int i = a; i <= b; i++)
            if (s[i] <= min)
            {
                min = s[i];     c = i;      
            }
        for (int i = a; i <= b; i++)
        {
            if (i <= c) code[i] += "0"; 
            else code[i] += "1";        
        }

        if (c == a)
            fano(c + 1, b);
        else if (c == b - 1)
            fano(a, c);
        else
        {
            fano(a, c); fano(c + 1, b);
        }
    }
}
void init()
{
    cout << "请输入信源符号个数n：";
    cin >> n;
    code = new string[n];
    cout << "请依次输入信源符号的概率：";
    for (int i = 0; i<n; i++) cin >> p[i];
    for (int i = 0; i<n - 1; i++)
        for (int j = i + 1; j<n; j++)
            if (p[i] < p[j])
            {
                double temp = p[i]; p[i] = p[j]; p[j] = temp;
            }
}

void solve()
{
    fano(0, n - 1);
    cout << endl << endl << setw(8) << "概率" << setw(8) << "码字"  << endl;
    for (int i = 0; i<n; i++)
        cout << setw(8) << p[i] << setw(8) << code[i] << setw(8) << endl;
    delete[]code;
}

int main()
{
    init();
    solve();
    return 0;
}

/*
测试数据：
6
0.32 0.22 0.18 0.16 0.08 0.04
8
0.25 0.25 0.125 0.125 0.0625 0.0625 0.0625 0.0625
*/

尾随后缀：

//代码：
#include <stdio.h>
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <ctype.h>
#include <algorithm>
#include <vector>
#include <string.h>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <time.h>

using namespace std;

int n, ok, num;
char s[100000][100], tmp[100];
char F[100000][100];
set<string> Ftmp;

void input()
{
    puts("请输入码字的个数：");
    cin >> n;
    puts("请输入码字：");
    for (int i = 1; i <= n; i++)
        scanf("%s", s[i]);
}

void Sort()
{
    for (int i = 1; i <= n; i++)
    {
        for (int j = i; j <= n; j++)
        {
            int len1 = strlen(s[i]);
            int len2 = strlen(s[j]);
            if (len1 > len2)
            {
                strcpy(tmp, s[i]);
                strcpy(s[i], s[j]);
                strcpy(s[j], tmp);
            }
        }
    }
}

bool isok(char a[], char b[])
{
    int len1 = strlen(a);
    int len2 = strlen(b);
    for (int i = 0; i < len1; i++)
    {
        if (a[i] != b[i])
            return false;
    }
    return true;
}

void init()
{
    Ftmp.clear();
    ok = 0;
    num = 0;
    for (int i = 1; i < n; i++)
    {
        for (int j = i + 1; j <= n; j++)
        {
            int len1 = strlen(s[i]);
            int len2 = strlen(s[j]);
            if (isok(s[i], s[j]))
            {
                strcpy(tmp, s[j] + len1);
                strcpy(F[num++], tmp);
            }
        }
    }
    for (int i = 0; i < num; i++)
        Ftmp.insert(F[i]);
}

void solve()
{
    int pos = 0;
    for (int i = 0; i < num; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            int len1 = strlen(F[i]);
            int len2 = strlen(s[j]);
            if (len1 < len2)
            {
                if (isok(F[i], s[j]))
                {
                    strcpy(tmp, s[j] + len1);
                    strcpy(F[num++], tmp);

                    int size = Ftmp.size();
                    Ftmp.insert(tmp);
                    if (Ftmp.size() == size)
                        num -= 1;
                }

            }
        }
    }
}

void test()
{
    puts("检验结果：");
    int ok = 0;
    for (int i = 0; i < num; i++)
    {
        if (ok) break;
        for (int j = 1; j <= n; j++)
        {
            if (!strcmp(F[i], s[j]))
            {
                puts("非唯一可译码");
                ok = 1;
                break;
            }
        }
    }
    if (!ok) puts("是唯一可译码");
    printf("\n");
    puts("尾随后缀集合是：");
    for (int i = 0; i < num; i++)
        Ftmp.insert(F[i]);
    set<string> ::iterator it;
    for (it = Ftmp.begin(); it != Ftmp.end(); it++)
        cout << *it << " "; cout << endl;

}

int main()
{
    input();
    Sort();
    init();
    solve();
    test();
    return 0;
}


//测试数据
/*
6
0 10 1100 1110 1011 1101

5
110 11 100 00 10
*/