浙江大学2018-19秋冬《数据结构基础》期中模拟练习
开始时间01/01/2016 8:00:00 AM
结束时间01/18/2038 8:00:00 AM
答题时长90分钟
考生Raul
得分92
总分100

判断题得分:12总分:15
1-1

If there are less than 20 inversions in an integer array, then Insertion Sort will be the best method among Quick Sort, Heap Sort and Insertion Sort. (3分)

       

评测结果
答案正确(3 分)

1-2

For a sequentially stored linear list of length NN, the time complexities for query and insertion are O(1)O(1) and O(N)O(N), respectively. (3分)

       

评测结果
答案错误(0 分)

1-3

In a binary search tree, the keys on the same level from left to right must be in sorted (non-decreasing) order. (3分)

       

评测结果
答案正确(3 分)

1-4

N2logNN^2 logN and NlogN2N logN^2 have the same speed of growth. (3分)

       

评测结果
答案正确(3 分)

1-5

If keys are pushed onto a stack in the order {1, 2, 3, 4, 5}, then it is impossible to obtain the output sequence {3, 4, 1, 2, 5}. (3分)

       

评测结果
答案正确(3 分)

单选题得分:59总分:64
2-1

For the quicksort implementation with the left pointer stops at an element with the same key as the pivot during the partitioning, but the right pointer does not stop in a similar case, what is the running time when all keys are equal? (5分)

评测结果
答案错误(0 分)

2-2

Given a quadtree(四叉树) with 3 nodes of degree 2, 2 nodes of degree 3, 4 nodes of degree 4. The number of leaf nodes in this tree is __. (5分)

评测结果
答案正确(5 分)

2-3

The result of performing three DeleteMin operations in the min-heap {1,3,2,6,7,5,4,15,14,12,9,10,11,13,8} is: (5分)

评测结果
答案正确(5 分)

2-4

Given input { 110, 119, 7, 911, 114, 120, 122 }. Which one of the following is the result after the 2nd run of the Least Signification Digit (LSD) radix sort? (5分)

评测结果
答案正确(5 分)

2-5

The recurrent equations for the time complexities of programs P1 and P2 are:

  • P1: T(1)=1T(1)=1, T(N)=T(N/2)+1T(N)=T(N/2)+1;
  • P2: T(1)=1T(1)=1, T(N)=2T(N/2)+1T(N)=2T(N/2)+1;

Then the correct conclusion about their time complexities is: (5分)

评测结果
答案正确(5 分)

2-6

For an in-order threaded binary tree, if the pre-order and in-order traversal sequences are B E A C F D and A E C B D F respectively, which pair of nodes' left links are both threads? (4分)

评测结果
答案正确(4 分)

2-7

Suppose that an array of size m is used to store a circular queue. If the front position is front and the current size is size, then the rear element must be at: (5分)

评测结果
答案正确(5 分)

2-8

To sort { 49, 38, 65, 97, 76, 13, 27, 50 } in increasing order, which of the following is the result after the 1st run of Shell sort with the initial increment 4? (5分)

评测结果
答案正确(5 分)

2-9

Insert { 3, 8, 9, 1, 2, 6 } one by one into an initially empty binary search tree. The post-order traversal sequence of the resulting tree is: (5分)

评测结果
答案正确(5 分)

2-10

In-order traversal of a binary tree can be done iteratively. Given the stack operation sequence as the following:

push(1), push(2), push(3), pop(), push(4), pop(), pop(), push(5), pop(), pop(), push(6), pop()

Which one of the following statements is TRUE? (5分)

评测结果
答案正确(5 分)

2-11

Among the following sorting methods, which ones will be slowed down if we store the elements in a linked structure instead of a sequential structure? (5分)

  1. Insertion sort; 2. Selection Sort; 3. Bubble sort; 4. Shell sort; 5. Heap sort
评测结果
答案正确(5 分)

2-12

In a complete binary tree with 1102 nodes, there must be __ leaf nodes. (5分)

评测结果
答案正确(5 分)

2-13

To delete p from a doubly linked list, we must do: (5分)

评测结果
答案正确(5 分)

程序填空题得分:15总分:15
5-1

The function is to sort the list { r[1] … r[n] } in non-decreasing order. Unlike selection sort which places only the minimum unsorted element in its correct position, this algorithm finds both the minimum and the maximum unsorted elements and places them into their final positions.

void  sort( list r[], int n )  
{
   int i, j, mini, maxi;

   for (i=1; i<n-i+1; i++) {
      mini = maxi = i;
      for( j=i+1; (3分); ++j ){
         if( (3分) ) mini = j; 
         else if(r[j]->key > r[maxi]->key) maxi = j;
      }
      if( mini != i ) swap(&r[mini], &r[i]);
      if( maxi != n-i+1 ){
         if( (3分) ) swap(&r[mini], &r[n-i+1]);
         else swap(&r[maxi], &r[n-i+1]);
      }
   }
} 
评测结果
答案正确(9 分)
测试点得分
序号结果得分
0答案正确3
1答案正确3
2答案正确3

5-2

The function is to find the K-th smallest element in a list A of N elements. The function BuildMaxHeap(H, K) is to arrange elements H[1] ... H[K] into a max-heap. Please complete the following program.

ElementType FindKthSmallest ( int A[], int N, int K )
{   /* it is assumed that K<=N */
    ElementType *H;
    int i, next, child;

    H = (ElementType *)malloc((K+1)*sizeof(ElementType));
    for ( i=1; i<=K; i++ ) H[i] = A[i-1];
    BuildMaxHeap(H, K);

    for ( next=K; next<N; next++ ) {
        H[0] = A[next];
        if ( H[0] < H[1] ) {
            for ( i=1; i*2<=K; i=child ) {
                child = i*2;
                if ( child!=K && (3分) ) child++;
                if ( (3分) )
                    H[i] = H[child];
                else break;
            }
            H[i] = H[0];
        }
    }
    return H[1];
}

评测结果
答案正确(6 分)
测试点得分
序号结果得分
0答案正确3
1答案正确3

函数题得分:6总分:6
6-1
No Less Than X in BST (6分)

You are supposed to output, in decreasing order, all the elements no less than X in a binary search tree T.

Format of function:

void Print_NLT( Tree T,  int X );

where Tree is defined as the following:

typedef struct TreeNode *Tree;
struct TreeNode {
    int Element;
    Tree  Left;
    Tree  Right;
};

The function is supposed to use Output(X) to print X.

Sample program of judge:

#include <stdio.h>
#include <stdlib.h>

typedef struct TreeNode *Tree;
struct TreeNode {
    int Element;
    Tree  Left;
    Tree  Right;
};

Tree BuildTree(); /* details omitted */
void Output( int X ); /* details omitted */

void Print_NLT( Tree T,  int X );

int main()
{
    Tree T;
    int X;

    T = BuildTree();
    scanf("%d", &X);
    Print_NLT( T, X );
    printf("End\n");

    return 0;
}

/* Your function will be put here */

Sample Output 1 (for the tree shown in Figure 1):

92 91 90 85 81 80 End

Figure 1

Sample Output 2 (for the tree shown in Figure 2):

End

Figure 2
编译器
GCC
代码
int array[10000];
int cnt=0;
void Print_NLT( Tree T,  int X ){
    Inorder(T);
    int i;
    for(i=0;i<cnt;i++){
        if(array[i]>=X) break;
    } 
    for(int j=cnt-1;j>=i;j--) Output(array[j]);
    return;
}

void Inorder(Tree T){
    if(!T) return;
    Inorder(T->Left);
    array[cnt++]=T->Element;
    Inorder(T->Right);
    

}
评测结果
答案正确(6 分)
编译器输出
a.c: In function ‘Print_NLT’:
a.c:63:5: warning: implicit declaration of function ‘Inorder’ [-Wimplicit-function-declaration]
     Inorder(T);
     ^~~~~~~
a.c: At top level:
a.c:72:6: warning: conflicting types for ‘Inorder’
 void Inorder(Tree T){
      ^~~~~~~
a.c:63:5: note: previous implicit declaration of ‘Inorder’ was here
     Inorder(T);
     ^~~~~~~
a.c: In function ‘BuildTree’:
a.c:33:6: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
      scanf("%d", &n);
      ^~~~~~~~~~~~~~~
a.c:35:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
          scanf("%d", &x);
          ^~~~~~~~~~~~~~~
a.c: In function ‘main’:
a.c:52:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &X);
     ^~~~~~~~~~~~~~~
测试点得分
测试点结果得分耗时内存
0答案正确220.00 ms204 KB
1答案正确124.00 ms328 KB
2答案正确18.00 ms212 KB
3答案正确110.00 ms200 KB
4答案正确112.00 ms204 KB