PTA 基础编程题目集 函数题 4-1~4-13
4-1//水题无难点
void PrintN(int N)
{
int i; for(i=1;i<=N;i++)
printf("%d\n",i);
}
4-2//水题无难点
double f( int n, double a[], double x )
{
double sum=0,ans=1;
for(int i=0;i<=n;i++)
{
sum+=a[i]*ans;
ans*=x;
}
return sum;
}
4-3//水题无难点
int Sum ( int List[], int N )
{
int sum=0;
for(int i=0;i
sum+=List[i];
return sum;
}
4-4//水题，精度记得乘一个1.0
ElementType Average( ElementType S[], int N )
{
float ans=0;
for(int i=0;i
ans+=S[i];
ans=ans/(N*1.0);
return ans;
}
4-5//水题，初始定义第一个为最大
ElementType Max( ElementType S[], int N )
{ float max=S[0];
for(int i=1;i
if(max
return max;
}
4-6//水题，可以打表或者直接计算
int FactorialSum( List L )
{
int num[13]={1,1,2,6,24,120,720,5040,40320,362880,3628800,39916800,479001600};
int sum=0;
List p=L;
while(p)
{
sum+=num[p->Data];
p=p->Next;
}
return sum;
}
4-7//水题，先判断是否是平方数，再判断有无相同的数
int IsTheNumber ( const int N )
{
int t=sqrt(N);
if(t*t!=N)return 0;
int num[10];
for(int i=0;i<10;i++)num[i]=0;
int x=N,p=0;
while(x)
{
num[x%10]++;
if(num[x%10]==2)return 1;
x=x/10;
}
return 0;
}
4-8//同4-6
int Factorial( const int N ){
int num[13]={1,1,2,6,24,120,720,5040,40320,362880,3628800,39916800,479001600};
if(N>=0)return num[N];
return 0;
}
4-9//水题记得判断0，0这个点
int Count_Digit ( const int N, const int D )
{
int ans=0,x=N;
if(x<0)x=-N;
while(x)
{
if(x%10==D)ans++;
x=x/10;
}
if(N==0&&D==0)return 1;
return ans;
}
4-10//大数乘法模仿大数加法
#include
void Print_Factorial ( const int N )
{
if(N<0)printf("Invalid input\n");
else if(N>=0&&N<=12)
{
int ans=1;
for(int i=1;i<=N;i++)
ans=ans*i;
printf("%d\n",ans);
}
else
{
char a[3001]="0080207226";
for(int i=14;i<=N;i++)
{
int ans=0,l=strlen(a);
for(int j=0;j
{
int temp=ans;
ans=((a[j]-'0')*i+ans)/10;
a[j]=((a[j]-'0')*i+temp)%10+'0';
}
while(ans)
{
a[strlen(a)]=ans%10+'0';
ans=ans/10;
}
}
for(int i=strlen(a)-1;i>=0;i--)
printf("%c",a[i]);
printf("\n");
}
}
4-11//归并排序，返回A[N/2]
void mer(float A[],float R[],int low,int mid,int hight)
{
int i=low,j=mid+1,k=low;
while(i<=mid&&j<=hight)
{
if(A[i]<=A[j])R[k++]=A[i++];
else R[k++]=A[j++];
}
while(i<=mid)R[k++]=A[i++];
while(j<=hight)R[k++]=A[j++];
for(i=low;i<=hight;i++)
A[i]=R[i];
}
void sort(float A[],float R[],int low,int hight)
{
if(low
{
int mid=(low+hight)/2;
sort(A,R,low,mid);
sort(A,R,mid+1,hight);
mer(A,R,low,mid,hight);
}
}
ElementType Median(ElementType A[], int N )
{
float R[MAXN];
sort(A,R,0,N-1);
return A[N/2];
}
4-12//水题，判断奇偶，位运算
int even( int n )
{
return !(n&1);
}
4-13//标准二分查找，水题
int binSearch(SeqList T, KeyType k)
{
int i=0,j=k;
while(i<=j)
{
int mid=(i+j)/2;
if(T.data[mid].key==k)return mid;
else if(T.data[mid].key>k)j=mid-1;
else i=mid+1;
}
return 0;
}