【PAT Advanced Level】1010. Radix (25)

这题参考了别人的代码，我写的总是有几个case过不去，也懒得找错误了。

#include <stdio.h>#include <string.h>long num2Dec(char *,int);//转换成10进制数据long findLowRadix(char *);//寻找最低进制数long binarysearch(char *,long ,long, long);int main(){char N1[11],N2[11];int tag,radix;long target = 0L,result=0L;long least;//进制最小long most;//进制最大scanf("%s%s",N1,N2);scanf("%d%d",&tag,&radix);if(1 == tag){target = num2Dec(N1,radix);least=findLowRadix(N2);most = (target + 1 > least + 1) ? target +1 :least +1; result = binarysearch(N2,least,most,target);if(result == -1)printf("Impossible");elseprintf("%d\n",result);}else if(2 == tag){target = num2Dec(N2,radix);least=findLowRadix(N1);most = (target + 1 > least + 1) ? target +1 :least +1; result = binarysearch(N1,least,most,target);if(result == -1)printf("Impossible");elseprintf("%d\n",result);}return 0;}long num2Dec(char *p,int radix){int len = strlen(p);int m=1,num=1,sum=0;int i=0;for(i=len-1;i>=0;i--){if(p[i]>='a' && p[i]<='z')num = p[i]-'a' + 10;else if(p[i] >= '0' && p[i] <= '9')num = p[i]-'0';sum += num*m;m*=radix;}return sum;}//ab:最小就是12进制  69：最小就是10进制long findLowRadix(char *p){long len=strlen(p),low=0,num=0,i=0;  for(i=len-1;i>=0;i--)  {  if(p[i]>='a'&&p[i]<='z')  num= p[i] - 'a' + 10;  else if(p[i]>='0'&& p[i]<='9')  num=p[i] - '0';  if(num+1>low)  low=num+1;  }  return low;  }long binarysearch(char *p,long low,long high,long target){long mid=low,tmp=0;while(low<=high){tmp = num2Dec(p,mid);if(tmp > target)high=mid-1;else if(tmp < target)low = mid+1;else return low;mid = (low+high)/2;}return -1;}