1. Learning summary
2.PTA experiment work
2.1 Topic 1:
7-1 jmu-is the string symmetrical
2.2 Design ideas
定义ElemType变量e，定义一个栈s，定义整型变量i，flag
为栈创建空间
for i=0 to str[i]不等于'\0'
将字符数组里的字符一一存放入栈
end for
for i=0 to str[i]不等于'\0'
将栈顶元素出栈，赋值给e
如果 str[i]跟e不相等
flag=1
end for
如果flag等于0
说明对称，输出yes
否则，输出no2.3 Code screenshots
2.4 PTA Submission List Description
The compiler forgot to change to c++
2.1 Topic 2:
7-3 Expression Conversion
2.2 Design ideas
定义栈S，定义整型变量i,j,定义字符变量e和字符数组str
读取字符串
创建栈S并申请空间
while str[i]不等于'\0'
如果是小数点，直接输出
如果是数字，直接输出
否则，如果是+
判断如果是代表正号，直接输出
如果是运算符，当栈顶运算符的优先级高于或等于该运算符则将栈顶运算符输出，直到栈顶运算符的优先级小于该运算符
否则压入栈
否则，如果是-
判断如果是代表负号，直接输出
如果是运算符，当栈顶运算符的优先级高于或等于该运算符则将栈顶运算符输出，直到栈顶运算符的优先级小于该运算符
否则压入栈
否则，如果是(
直接压入栈
否则，如果是）
将遇到第一个左括号之前的运算符都输出
否则，如果是*或/
如果栈顶运算符的优先级高于或等于该运算符则将栈顶运算符输出，直到栈顶运算符的优先级小于该运算符
否则压入栈
end while
当栈不为空时，将栈里的元素都输出2.3 Code screenshots
2.4 PTA Submission List Description
The first time I didn't take into account the decimal situation, after the modification, this test point is correct.
The test point that there is a positive and negative sign before the operand has been changed for a long time. I don’t know that the positive sign does not need to be output. When I asked the Baidu question later, I saw someone else listed the test data, so I tried it. I didn’t expect it to be right.
2.1 Topic 3:
7-1 jmu-count game
2.2 Design ideas
定义整型变量count=0,e,k,i,n,m,定义队列game
输入n、m的值
如果n小于m
输出error!
否则
初始化队列game
for i=1 to i小于等于n
按顺序入队列
end for
while队列不为空
第一个元素出队列并报数count++
如果报的数count为m
将这个元素输出
count重新赋值为0
否则这个元素继续进入队列
end while
2.3 Code screenshots
2.4 PTA Submission List Description
The first time I did it was the previous method. After listening to the teacher talk about a similar topic, I suddenly understood how to use the queue to do it.
3. Screenshot of the PTA final ranking of this week's topic set
3.1 Stack PTA ranking
3.2 Cohort PTA ranking
3.3 My total score:
209
4. Read the code
/*
借助栈 非递归遍历二叉树
2018.4.1
*/
#include<stdio.h>
#include<stdlib.h>
//返回的结果
typedef enum{
ERROR,SUCCESS
}STATUS;
//结点的数据类型
typedef char TREEELEM;
//二叉树结点
typedef struct BinTreeNode{
TREEELEM data;
struct BinTreeNode* lChild,*rChild;
}BinTreeNode,*PtrToBinTree;
typedef PtrToBinTree STACKELEM;
//栈结点
typedef struct StackLinkNode{
STACKELEM data;
struct StackLinkNode * next;
}StackLinkNode,*PtrToLinkStack;
//////////////////////栈//操//作//开//始/////////////////////////////////////
//创建栈
STATUS CreateStackLink(PtrToLinkStack *S){
*S = (PtrToLinkStack)malloc(sizeof(StackLinkNode));
if(*S){
(*S)->next = NULL;
return SUCCESS;
}
return ERROR;
}
//栈判空
bool EmptyStack(PtrToLinkStack S){
if(S->next){
return false;
}
return true;
}
//压栈
STATUS Push(PtrToLinkStack S,STACKELEM e){
PtrToLinkStack temp = (PtrToLinkStack)malloc(sizeof(StackLinkNode));
if(!temp){
return ERROR;
}
temp->data = e;
temp->next = S->next;
S->next = temp;
return SUCCESS;
}
//出栈
STACKELEM Pop(PtrToLinkStack S){
if(EmptyStack(S)){
return NULL;
}
PtrToLinkStack temp = S->next;
S->next = temp->next;
STACKELEM data = temp->data;
free(temp);
return data;
}
//获取栈顶元素
STACKELEM GetTop(PtrToLinkStack S){
return S->next->data;
}
//测试栈操作
//void TestStack(){
// PtrToLinkStack S;
// CreateStackLink(&S);
// int n;
// char c;
// scanf("%d",&n);
// getchar();
// while(n--){
// scanf("%c",&c);
// Push(S,c);
// }
// c = GetTop(S);
// printf("%c\n",c);
// while(!EmptyStack(S)){
// c = Pop(S);
// printf("%c ",c);
// }
// printf("\n");
//}
//////////////////////栈//操//作//结//束/////////////////////////////////////
///////////////////////树//操//作//开//始/////////////////////////////////////
/*
按先序序列输入，如果结点为空请输入“#”
*/
void Create(PtrToBinTree *T){
char c;
scanf("%c",&c);
if(c == '#'){
*T = NULL;
return ;
}
*T = (PtrToBinTree)malloc(sizeof(BinTreeNode));
(*T)->data = c;
Create(&((*T)->lChild));
Create(&((*T)->rChild));
}
/*
访问树结点
*/
void Visit(PtrToBinTree p){
if(p){
printf("%c ",p->data);
}
}
/*
中序遍历非递归算法
*/
void NRInOrd(PtrToBinTree T){
PtrToLinkStack S;
CreateStackLink(&S);
PtrToBinTree p = T;
while(p || !EmptyStack(S)){
if(p){
Push(S,p);
p = p->lChild;
} else {
p = Pop(S);
Visit(p);
p = p->rChild;
}
}
printf("\n");
}
/*
先序遍历非递归算法
*/
void NRPreOrd(PtrToBinTree T){
PtrToLinkStack S;
CreateStackLink(&S);
PtrToBinTree p = T;
while(p || !EmptyStack(S)){
if(p){
Visit(p);
Push(S,p);
p = p->lChild;
} else {
p = Pop(S);
p= p->rChild;
}
}
printf("\n");
}
/*
后序遍历非递归算法
*/
void NRPostOrd(PtrToBinTree T){
PtrToLinkStack S;
CreateStackLink(&S);
PtrToBinTree p,r;
p = T;
r = NULL;
while(p || !EmptyStack(S)){
if(p){
Push(S,p);
p = p->lChild;
} else {
p = GetTop(S);
if(p->rChild && p->rChild!=r){
p = p->rChild;
Push(S,p);
p = p->lChild;
} else{
p = Pop(S);
Visit(p);
r = p;
p = NULL;
}
}
}
printf("\n");
}
int main(){
//TestStack();
PtrToBinTree T;
Create(&T);
//中序非递归遍历
NRInOrd(T);
//先序非递归遍历
NRPreOrd(T);
//后序非递归遍历
NRPostOrd(T);
return 0;
}The code address is
https://gitee.com/MoZhaMiao/codes/qhol864mxi31dzbegnjr244
This code uses the stack method to implement the pre-order, in-order, and post-order traversal of the binary tree. Recently, I was just learning binary trees. When I was learning, the textbook used the recursive method.
5. Screenshot of code Git commit record
