zoj 1102 Phylogenetic Trees I...

#include<cstdio>#include<cstring>char seq[1100][1100];int n,l;int heap[2200];int main(){    while(scanf("%d%d",&n,&l)&&(n||l))    {     int cost=0;     for(int i=1;i<=n;i++)     scanf("%s",seq[i]);     for(int k=1;k<=l;k++)     {  for(int i=1;i<=n;i++)  heap[n+i-1]=1<<(seq[i][k-1]-'A');  for(int i=n-1;i>=1;i--)  {          if(heap[i]=(heap[2*i]&heap[2*i+1]));          else          {          heap[i]=heap[2*i]|heap[2*i+1];          cost++;          }  }  int ch=0;  while(!(heap[1]&1))  {          ch++;          heap[1]>>=1;  }  printf("%c",ch+'A');     }          printf(" %dn",cost);    }     return 0;}