Entropy（哈弗曼编码，优先队列）

来源：互联网发布：kali linux gnuradio 编辑：程序博客网时间：2024/05/27 01:49

</pre><pre name="code" class="cpp">坑在只有一个字符的时候

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<queue>using namespace std;#define maxn 1005#define inf 0x3f3f3f3fint main(){    char s[maxn];    int a[maxn];    freopen("in.txt","r",stdin);    while(gets(s)){        if(!strcmp(s,"END"))break;        int m=0;        int sum=0;        m=strlen(s);        priority_queue<int>q;        memset(a,0,sizeof a);        for(int i=0;i<m;i++){            if(s[i]>='A'&&s[i]<='Z')            a[s[i]-'A'+1]++;            else a[0]++;        }        for(int i=0;i<=26;i++)            if(a[i]>0)q.push(-a[i]);        if(q.size()==1)sum+=-(q.top());        else{        while(q.size()>1){            int a=-q.top();            q.pop();            int b=-q.top();            q.pop();            sum+=a+b;            q.push(-(a+b));        }        }        printf("%d %d %.1f\n",m*8,sum,1.0*m*8/sum);    }}

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