ReviewForJob(3)表、栈和队列

【0】表ADT

1）intro：我们把 形如 A1, A2, A3, ..., An 的结构称为表；

2）表的实现： 数组（循环数组） 或 链表 或 双链表 或 循环链表实现；

3）表的插入，删除操作可以在任意位置上进行；

【1】栈（基于表）

1）intro：栈是限制插入和删除只能在一个位置上进行的的表；

2）栈的实现： 数组实现 或 链表实现；

3）栈的应用

应用荔枝1）检验代码的平衡符号：每一个 括号（圆括号，中括号，花括号） 都要一一对应；

Attention）stack.h如下：

#include <stdio.h>#include <malloc.h>#define ElementType char#define ERROR(str) printf(str)struct Stack;typedef struct Stack *Stack;struct Stack{int size;ElementType* head;int top;};int isFull(Stack s);int isEmpty(Stack s);Stack initStack(int size);void push(Stack s, ElementType c);void pop(Stack s, ElementType *e);int isFull(Stack s){return s->size == s->top ? 1 : 0;}int isEmpty(Stack s){return 0 == s->top ? 1 : 0;}Stack initStack(int size){Stack s = (Stack)malloc(sizeof(struct Stack));if(s==NULL){ERROR("error: failed initStack() for there is no spare space.\n");}else {s->size = size;s->top = 0;s->head = (ElementType*)malloc(sizeof(ElementType) * size);if(s->head==NULL){ERROR("error: failed initStack() for there is no spare space.\n");return NULL;}}return s;}void push(Stack s, ElementType c){if(!isFull(s)){s->head[s->top++] = c;} else{printf("%s", "failed pushing for stack is full.");}}void pop(Stack s, ElementType *e){if(!isEmpty(s)){*e = s->head[--s->top];}else{*e = ' ';printf("%s", "failed poping for stack is empty.");}}

</pre><pre code_snippet_id="1797122" snippet_file_name="blog_20160731_3_2765700" name="code" class="cpp">#include "stack.h"// check whether the grammar defined in given file is correct or not.int checkFile(Stack s){FILE *fp;ElementType c;ElementType popc;fp = fopen("D:\\classical_books\\datastructure_alg\\source_code\\chapter3\\review_for_job\\p52_check_balanced_char\\temp.txt", "r");// only test for round bracket '()', bracket '[]', brace'{}'.// do you know the meanings of open brace '{' and close brace '}'.while((c=getc(fp)) != EOF){if(c == '(' || c == '[' || c == '{'){push(s, c);}else if(c == ')' || c == ']' || c == '}'){pop(s, &popc);if(c==')' && popc!= '('){ return 0;}else if(c==']' && popc!= '['){ return 0;}else if(c=='}' && popc!= '{'){ return 0;}}}return 1;}int main(){Stack s;int result;s = initStack(1000);if(s==NULL){return -1;}result = checkFile(s);printf("%d \n", result);return 0;}

应用荔枝2）计算后缀表达式的值：step1）将中缀表达式转为 后缀表达式；step2）然后求 后缀表达式的值；

Attention）infix2postfix.h 见应用荔枝3；

#include "infix2postfix.h" void computeExpr(Stack s, ElementType *postfix, int length){int i = 0;char c;ElementType num1, num2, result;for(;i<length;i++){c = postfix[i];if(isOperator(c) == -1)// c is an operand.{push(s, c-48);}else if(isOperator(c) != -1) // c is an operator.{pop(s, &num1);pop(s, &num2);switch(c){case '+': result = num1+num2;break;case '-': result = num1-num2;break;case '*': result = num1*num2;break;case '/': result = num1/num2;break;}push(s, result);}}pop(s, &result);printf("final computing result is %d \n", result);}int main(){Stack s;ElementType output[255];int length;s = initStack(1000);if(s==NULL){return -1;}length = infix2postfix(s, output); //switch infix into postfix.printChatArray(output, length);// compute postfix expr.free(s);s=initStack(1000);computeExpr(s, output, length);return 0;}

应用荔枝3）中缀表达式： 中缀转后缀表达式；

stack.h 同上 && infix2postfix.h 如下：

#include "stack.h"#include "math.h"void printChatArray(ElementType* array, int size);int isOperator(ElementType c);int checkPriority(int p1, int p2);int infix2postfix(Stack s, ElementType *output);// just print array.void printChatArray(ElementType* array, int size){int i=0;for(;i<size; i++){putchar(array[i]);}printf("\n\n");}// check whether the char is operator or not.// if true returns priority with array index ,otherwise return -1.int isOperator(ElementType c){ int i = 0;char priorities[] = {'(', ' ', '+','-',' ','*','/'};int size = 7;for(; i<size; i++){if(c==priorities[i]){return i;}}return -1;} // 0 means p1.priority == p2.priority// 1                    >// -1                   <int checkPriority(int p1, int p2){if(p1-p2==1 || p1-p2==-1 || p1-p2==0){return 0;}else if(p1-p2>1){return 1;}else if(p1-p2 < -1){return -1;}}// transmit infix into postfix.// attention for operands not being pushed into stack.int infix2postfix(Stack s, ElementType *output){ElementType c, popc, topc;int i = 0;int p1, p2;printf("%s", "input the expr: ");while((c=getchar()) != '\n'){if(c=='(') // when the char is ( or ){push(s, c);}else if(c==')'){while(!isEmpty(s) && (topc=getTop(s))!='('){pop(s, &popc);output[i++] = popc;}if(topc=='('){pop(s,&popc);}} // when the char is ( or ) over.else if(isOperator(c) == -1) // c is an operand.{output[i++] = c;}else if((p1=isOperator(c)) != -1) // c is an operator.{if(isEmpty(s)) // if the stack is empty.{push(s, c);}else  // if the stack is not empty.{while(!isEmpty(s)){topc = getTop(s);// after that, check priority between c and topc.p2 = isOperator(topc);if(checkPriority(p1,p2) != 1) // p1.priority <= p2.priority, then pop operand under p2 into output array.{pop(s, &popc);output[i++] = popc;}else{break;}}push(s, c);}}}while(!isEmpty(s)) // pop surplus elements into output array.{pop(s, &popc);output[i++] = popc;}return i;}

#include "infix2postfix.h" int main(){Stack s;ElementType output[255];int length;s = initStack(1000);if(s==NULL){return -1;}length = infix2postfix(s, output); //switch infix into postfix.printChatArray(output, length); return 0;}

【2】队列（基于表）

1）intro：队列是插入在一端，而删除在另一端的表；

2）队列的实现：数组实现 或  循环数组（队列）实现；

3）（循环队列）代码如下：

#include <stdio.h>#include <malloc.h>#define ElementType int#define Error(str) printf("\nerror: %s", str)struct Queue;typedef struct Queue* Queue;// 循环队列的数据结构.struct Queue{int capacity;int front;int rear;int size;ElementType* array;};Queue initQueue(int capacity);int isFull(Queue queue);void enQueue(Queue queue, ElementType e);int isEmpty(Queue queue);ElementType deQueue(Queue queue);void printQueue(Queue queue);// init queue wit capacity.Queue initQueue(int capacity){// allocate memory for queue.Queue queue = (Queue)malloc(sizeof(struct Queue));if(queue==NULL){Error("failed initQueue() for out of space.");return NULL;}queue->capacity = capacity;queue->front = 0;queue->rear = 0;queue->size = 0;// allocate memory for queue->array.queue->array = (ElementType*)malloc(capacity * sizeof(ElementType));if(queue->array == NULL){Error("failed initQueue() for out of space.");return NULL;}return queue;}// judge whether the queue is full or not.int isFull(Queue queue){return queue->size == queue->capacity ? 1 : 0;}// 进队列，满时不进.void enQueue(Queue queue, ElementType e){if(isFull(queue)){Error("failed enQueue() for the queue is full.");return ;}queue->array[queue->rear++ % queue->capacity] = e;queue->size++;}// judge whether the queue is empty or not.int isEmpty(Queue queue){return queue->size == 0 ? 1 : 0;}// 出队列，空时不出.ElementType deQueue(Queue queue){int temp;if(isEmpty(queue)){Error("failed deQueue() for the queue is empty.");return -1;}temp = queue->array[queue->front++ % queue->capacity];queue->size--;return temp;}// 打印队列void printQueue(Queue queue){int i, index;ElementType* array = queue->array;printf("\n");for(i=0; i<queue->size; i++){index = (queue->front + i) % queue->capacity;printf("%d ", array[index]);}printf("\n");}// 打印队列所在数组void printArray(Queue queue){int i;printf("\nelements in queue->array from index 0 are as follows: ");for(i=0; i<queue->size; i++){printf("%d ", queue->array[i]);}printf("\n");}

#include "queue.h"void main(){ElementType array[] = {3, 4, 6, 1, 2, 0, 10, 8, 9};Queue queue;int capacity=6;int i;queue=initQueue(capacity); // 初始化队列if(queue == NULL){return ;}printf("\nlet {3, 4, 6, 1, 2, 0, 10, 8, 9} enter queue.\n");for(i=0; i<9; i++){enQueue(queue, array[i]); // 让元素进队列}printf("\n\nthe elements in queue are as follows: ");printQueue(queue);// 让元素出队列deQueue(queue);deQueue(queue);deQueue(queue);enQueue(queue, array[6]);enQueue(queue, array[7]);enQueue(queue, array[8]);printf("\n\nafter 3 dequeue operations and enQueue({10,8,9}) ,the elements in queue are as follows: ");printQueue(queue);printArray(queue);}