xmu 1312求导 WA什么状况修改后运行超时

#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main()
{
//	freopen("1.txt","r",stdin);
int a[1001],t1,t2,flag=0,f=0;
int i=0,n;
char c[1001],temp,buf[1000];
memset(a,0,sizeof(a));
memset(buf,0,sizeof(buf));
fgets(buf,1000,stdin);
n=strlen(buf);
while(i<n-1)
{
t1=0;
t2=0;
if(buf[i]=='-')
{
temp='-';
i++;
}
else if(buf[i]=='+')
{
temp='+';
i++;
}
else
temp='+';
if(buf[i]=='0')
{
i++;
while(buf[i]=='0')
i++;
if(!isdigit(buf[i]))
{
while(buf[i]!='+'&&buf[i]!='-'&& i!=n-1)
i++;
continue;
}
}
while(isdigit(buf[i]))
{
t1=t1*10+(buf[i]-'0');
i++;
}
if(t1==0)
t1=1;
if(buf[i]=='x')
{
i++;
if(buf[i]=='^')
{
i++;
while(isdigit(buf[i]))
{
t2=t2*10+(buf[i]-'0');
i++;
}
if(temp=='+')
a[t2]+=t1;
if(temp=='-')
a[t2]-=t1;
}
else
{
if(temp=='+')
a[1]+=t1;
if(temp=='-')
a[1]-=t1;
}
}
else
continue;

}

for(i=1;i<=1000;i++)
{
if(a[i]!=0)
{
a[i-1]=a[i]*i;
a[i]=0;
}

}
for(i=0;i<1000;i++)
if(a[i]!=0)
{
f=1;
break;
}
for(i=1000;i>=0;i--)
{
if(f==0)
{
printf("%d",f);
break;
};

if(a[i]!=0)
{

if(flag==0 &&a[i]>0)
{
flag=1;
}
else
{
if(a[i]>0)
putchar('+');
flag=1;
}
if(a[i]==-1)
putchar('-');
else if(a[i]!=1)
printf("%d",a[i]);
if(i==0)
break;
putchar('x');
if(i>1)
{
putchar('^');
printf("%d",i);
}
}
}
putchar('\n');
}

修改后运行超时#include<stdio.h>#include<string.h>#include<ctype.h>int main(){//	freopen("1.txt","r",stdin);int a[1001],b[10],t1,t2,flag=0,f=0;int i=0,j,n;char c[1001],temp,buf[1000];memset(a,0,sizeof(a));memset(b,-1,sizeof(b));memset(buf,0,sizeof(buf));fgets(buf,1000,stdin);n=strlen(buf);while(i<n-1){t1=0;t2=0;if(buf[i]=='-'){temp='-';i++;}else if(buf[i]=='+'){temp='+';i++;}elsetemp='+';if(buf[i]=='0'){i++;while(buf[i]=='0')i++;if(!isdigit(buf[i])){while(buf[i]!='+'&&buf[i]!='-'&& i!=n-1)i++;continue;}}while(isdigit(buf[i])){t1=t1*10+(buf[i]-'0');i++;}if(t1==0)t1=1;if(buf[i]=='x'){i++;if(buf[i]=='^'){i++;while(isdigit(buf[i])){t2=t2*10+(buf[i]-'0');i++;}if(temp=='+')a[t2]+=t1;if(temp=='-')a[t2]-=t1;}else{if(temp=='+')a[1]+=t1;if(temp=='-')a[1]-=t1;}}elsecontinue;}for(j=0,i=1;i<=1000;i++){if(a[i]!=0){f=1;b[j++]=i-1;a[i-1]=a[i]*i;a[i]=0;}}if(f==0)printf("%d",f);else{for(i=9;i>=0;i--){if(b[i]!=-1){if(flag==0 &&a[b[i]]>0){flag=1;}else{if(a[b[i]]>0)putchar('+');flag=1;}if(a[b[i]]==-1)putchar('-');elseprintf("%d",a[b[i]]);if(b[i]==0)break;putchar('x');if(b[i]>1){putchar('^');printf("%d",b[i]);}}}}putchar('\n');}