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)
In a binary search tree, the keys on the same level from left to right must be in sorted (non-decreasing) order. (3分)
and have the same speed of growth. (3分)
For a sequentially stored linear list of length , the time complexities for deleting the first element and inserting the last element are and , respectively. (3分)
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)
The recurrent equations for the time complexities of programs P1 and P2 are:
Then the correct conclusion about their time complexities is: (5分)
For the quicksort implementation with neither the left nor the right pointer stops when an element with the same key as the pivot is found during the partitioning, what is the running time when all keys are equal? (5分)
To sort { 8, 3, 9, 11, 2, 1, 4, 7, 5, 10, 6 } by Shell Sort, if we obtain ( 4, 2, 1, 8, 3, 5, 10, 6, 9, 11, 7 ) after the first run, and ( 1, 2, 3, 5, 4, 6, 7, 8, 9, 11, 10 ) after the second run, then the increments of these two runs must be __ , respectively. (5分)
To insert s
after p
in a doubly linked circular list, we must do: (5分)
The result of performing three DeleteMin operations in the min-heap {1,3,2,12,6,4,8,15,14,9,7,5,11,13,10} is: (5分)
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)
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)
Insert { 6, 9, 12, 3, 4, 8 } one by one into an initially empty binary search tree. The post-order traversal sequence of the resulting tree is: (5分)
Suppose that an array of size m
is used to store a circular queue. If the head pointer front
and the current size variable size
are used to represent the range of the queue instead of front
and rear
, then the maximum capacity of this queue can be: (5分)
Given input { 4321, 56, 57, 46, 289, 17, 331, 33, 234, 63 }. Which one of the following is the result after the 1st run of the Least Signification Digit (LSD) radix sort? (5分)
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)
How many leaf node does a complete binary tree with 2435 nodes have? (5分)
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)
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]);
}
}
}
序号 | 结果 | 得分 |
---|---|---|
0 | 答案错误 | 0 |
1 | 答案正确 | 3 |
2 | 答案正确 | 3 |
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];
}
序号 | 结果 | 得分 |
---|---|---|
0 | 答案正确 | 3 |
1 | 答案正确 | 3 |
You are supposed to output, in decreasing order, all the elements no greater than X
in a binary search tree T
.
void Print_NGT( 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
.
#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_NGT( Tree T, int X );
int main()
{
Tree T;
int X;
T = BuildTree();
scanf("%d", &X);
Print_NGT( T, X );
printf("End\n");
return 0;
}
/* Your function will be put here */
91 90 85 81 80 55 End
End
/*#include <stdio.h> #include <stdlib.h> typedef struct TreeNode *Tree; struct TreeNode { int Element; Tree Left; Tree Right; }; Tree BuildTree(); void Output( int X ); void Print_NGT( Tree T, int X ); int main() { Tree T; int X; T = BuildTree(); scanf("%d", &X); Print_NGT( T, X ); printf("End\n"); return 0; } Your function will be put here */ int a[1000] = {0}, st = -1; int cmp(const void *a, const void *b) { return *(int *)b - *(int *)a; } void Tr(Tree T, int X) { if (T) { if (T->Element <= X) { a[++st] = T->Element; } Tr(T->Left, X); Tr(T->Right, X); } } void Print_NGT( Tree T, int X ) { Tr(T, X); qsort(a, st+1, sizeof(int), cmp); for (int i = 0; i<=st; i++) { Output(a[i]); } }
测试点 | 结果 | 得分 | 耗时 | 内存 |
---|---|---|---|---|
0 | 答案正确 | 2 | 3 ms | 256 KB |
1 | 答案正确 | 1 | 4 ms | 256 KB |
2 | 答案正确 | 1 | 4 ms | 256 KB |
3 | 答案正确 | 1 | 3 ms | 256 KB |
4 | 答案正确 | 1 | 4 ms | 256 KB |
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); ^~~~~~~~~~~~~~~