http://poj.org/problem?id=1789
1 #include <string.h> 2 #include <stdio.h> 3 #include <stdlib.h> 4 #define INF 0x0fffffff 5 int mat[2002][2002]; 6 int N; 7 typedef struct Code { 8 char str[10]; 9 }Code; 10 Code codes[2002]; 11 int calc(char *str1,char *str2) 12 { 13 char *p=str1,*q=str2; 14 int count=0; 15 while(*p&&*q) { 16 if((*p)!=(*q)) 17 count++; 18 p++; 19 q++; 20 } 21 return count; 22 } 23 int prim() 24 { 25 int start=0; 26 bool visited[2002]={false}; 27 int nearest[2002]; 28 int min_cost=0; 29 int min=INF; 30 int pos; 31 int i,j; 32 for(i=0;i<N;i++) 33 nearest[i]=mat[start][i]; 34 visited[start]=true; 35 nearest[start]=0; 36 for(i=1;i<N;i++) { 37 min=INF; 38 for(j=0;j<N;j++) { 39 if(!visited[j]&&nearest[j]<min) { 40 min=nearest[j]; 41 pos=j; 42 } 43 } 44 min_cost+=min; 45 visited[pos]=true; 46 for(j=0;j<N;j++) 47 if(!visited[j]&&nearest[j]>mat[pos][j]) 48 nearest[j]=mat[pos][j]; 49 } 50 return min_cost; 51 } 52 int main() 53 { 54 while(scanf("%d",&N)!=EOF) { 55 if(N==0) 56 return 0; 57 int i,j; 58 for(i=0;i<N;i++) { 59 scanf("%s",codes[i].str); 60 } 61 for(i=0;i<N;i++) 62 for(j=0;j<=i;j++) 63 if(i==j) 64 mat[i][j]=INF; 65 else mat[j][i]=mat[i][j]=calc(codes[i].str,codes[j].str); 66 printf("The highest possible quality is 1/%d.\n",prim()); 67 } 68 return 0; 69 }