http://acm.hdu.edu.cn/showproblem.php?pid=1053
哈夫曼树
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1 //1053 2 #include <cstdio> 3 #include <cstring> 4 #include <queue> 5 using namespace std; 6 7 const int L=10000,N=60; 8 char str[L]; 9 int c[30]; 10 int lch[N],rch[N],w[N],sz; 11 typedef pair<int,int> pii; 12 priority_queue<pii,vector<pii>,greater<pii> > q; 13 int dfs(int p,int h) 14 { 15 if(lch[p]==0 && rch[p]==0) 16 return w[p]*h; 17 return dfs(lch[p],h+1)+dfs(rch[p],h+1); 18 } 19 int main() 20 { 21 while(scanf("%s",str),strcmp(str,"END")) 22 { 23 memset(c,0,sizeof(c)); 24 for(int i=0;str[i];i++) 25 { 26 int ch = str[i]=='_'?26:str[i]-'A'; 27 c[ch]++; 28 } 29 sz=0; 30 for(int i=0;i<=26;i++) if(c[i]>0) 31 { 32 sz++; 33 w[sz]=c[i]; 34 lch[sz]=rch[sz]=0; 35 q.push(make_pair(w[sz],sz)); 36 } 37 int n=sz; 38 for(int i=1;i<n;i++) 39 { 40 int a=q.top().second; q.pop(); 41 int b=q.top().second; q.pop(); 42 sz++; 43 w[sz]=w[a]+w[b]; 44 lch[sz]=a; rch[sz]=b; 45 q.push(make_pair(w[sz],sz)); 46 } 47 q.pop(); 48 int s1=strlen(str)*8; 49 int s2 = n==1?w[sz]:dfs(sz,0); 50 printf("%d %d %.1lf\n",s1,s2,(double)s1/s2); 51 } 52 return 0; 53 }
