做这几天的数据结构的题目的时候有很多函数需要填写，这里需要有一个大致的顺序，一般是先补全结构体，也就是创建队列 | 栈；
而后初始化，设置初值create（）函数，再然后C语言需要释放，补全释放函数也就是free；
这下可以根据题目要求进行操作了，一般情况下模拟操作自己是可以做出来的，但是像我第一次看到这个题目肯定是一脸懵逼，只有看了视频才知道。
数据结构我感觉就是孰能生巧的东西，不像算法变化很多，还是要多敲代码记住就可以了。
第一种：这里初始化顶部为0，所以要访问顶部的话需要-1再进行访问。
// 题目要求两个栈,这里用数组创建两个栈
typedef struct {
int stackin[30000], topin;
int stackout[30000], topout;
} MyQueue;
/** Initialize your data structure here. */
//创建"队列",初始化
MyQueue* myQueueCreate() {
MyQueue * obj = (MyQueue *)malloc(sizeof(MyQueue));
obj->topin = 0;
obj->topout = 0;
return obj;
}
/** 往队列中加入元素. */
void myQueuePush(MyQueue* obj, int x) {
obj->stackin[obj->topin++] = x;
}
/** 移除队列的头部 */
int myQueuePop(MyQueue* obj) {
if(obj->topout == 0) {
while(obj->topin) {
obj->stackout[obj->topout++] = obj->stackin[--obj->topin];
}
}
return obj->stackout[--obj->topout];
}
/** 获取队列的头部(不删除). */
int myQueuePeek(MyQueue* obj) {
if(obj->topout == 0) {
while(obj->topin) {
obj->stackout[obj->topout++] = obj->stackin[--obj->topin];
}
}
return obj->stackout[obj->topout - 1];
}
/** 判断队列是否为空. */
bool myQueueEmpty(MyQueue* obj) {
return obj->topin + obj->topout == 0;
}
// 释放队列
void myQueueFree(MyQueue* obj) {
free(obj);
}
/**
* Your MyQueue struct will be instantiated and called as such:
* MyQueue* obj = myQueueCreate();
* myQueuePush(obj, x);
* int param_2 = myQueuePop(obj);
* int param_3 = myQueuePeek(obj);
* bool param_4 = myQueueEmpty(obj);
* myQueueFree(obj);
*/
第二种：这里初始化顶部为1
typedef struct {
int stackin[30000], topin;
int stackout[30000], topout;
} MyQueue;
/** Initialize your data structure here. */
MyQueue* myQueueCreate() {
MyQueue * obj = (MyQueue *)malloc(sizeof(MyQueue));
obj->topin = -1;
obj->topout = -1;
return obj;
}
/** Push element x to the back of queue. */
void myQueuePush(MyQueue* obj, int x) {
obj->stackin[++obj->topin] = x;
}
/** Removes the element from in front of queue and returns that element. */
int myQueuePop(MyQueue* obj) {
if(obj->topout == -1) {
while(obj->topin != -1) {
obj->stackout[++obj->topout] = obj->stackin[obj->topin--];
}
}
return obj->stackout[obj->topout--];
}
/** Get the front element. */
int myQueuePeek(MyQueue* obj) {
if(obj->topout == -1) {
while(obj->topin != -1) {
obj->stackout[++obj->topout] = obj->stackin[obj->topin--];
}
}
return obj->stackout[obj->topout];
}
/** Returns whether the queue is empty. */
bool myQueueEmpty(MyQueue* obj) {
return obj->topin + obj->topout == -2;
}
void myQueueFree(MyQueue* obj) {
free(obj);
}
/**
* Your MyQueue struct will be instantiated and called as such:
* MyQueue* obj = myQueueCreate();
* myQueuePush(obj, x);
* int param_2 = myQueuePop(obj);
* int param_3 = myQueuePeek(obj);
* bool param_4 = myQueueEmpty(obj);
* myQueueFree(obj);
*/
这里删除图书那里，和上一题不一样，上一题保证没有空的，但这一题是有空的，这里需要进行一个判断，如果两个栈都为空则返回-1；
typedef struct {
int stackin[10001], topin;
int stackout[10001], topout;
} CQueue;
CQueue* cQueueCreate() {
CQueue * obj = (CQueue *)malloc(sizeof(CQueue));
obj->topin = 0;
obj->topout = 0;
return obj;
}
void cQueueAppendTail(CQueue* obj, int value) {
obj->stackin[obj->topin++] = value;
}
int cQueueDeleteHead(CQueue* obj) {
if(obj->topout == 0) {
while(obj->topin) {
obj->stackout[obj->topout++] = obj->stackin[--obj->topin];
}
}
if(obj->topout == 0) {
return -1;
}else {
return obj->stackout[--obj->topout];
}
}
void cQueueFree(CQueue* obj) {
free(obj);
}
/**
* Your CQueue struct will be instantiated and called as such:
* CQueue* obj = cQueueCreate();
* cQueueAppendTail(obj, value);
* int param_2 = cQueueDeleteHead(obj);
* cQueueFree(obj);
*/
typedef struct {
int stackin[101], topin;
int stackout[101], topout;
} MyQueue;
MyQueue* myQueueCreate() {
MyQueue * obj = (MyQueue *)malloc(sizeof(MyQueue));
obj->topin = -1;
obj->topout = -1;
return obj;
}
void myQueuePush(MyQueue* obj, int x) {
obj->stackin[++obj->topin] = x;
}
int myQueuePop(MyQueue* obj) {
if(obj->topout == -1) {
while(obj->topin != -1) {
obj->stackout[++obj->topout] = obj->stackin[obj->topin--];
}
}
return obj->stackout[obj->topout--];
}
int myQueuePeek(MyQueue* obj) {
if(obj->topout == -1) {
while(obj->topin != -1) {
obj->stackout[++obj->topout] = obj->stackin[obj->topin--];
}
}
return obj->stackout[obj->topout];
}
bool myQueueEmpty(MyQueue* obj) {
return obj->topin + obj->topout == -2;
}
void myQueueFree(MyQueue* obj) {
free(obj);
}
/**
* Your MyQueue struct will be instantiated and called as such:
* MyQueue* obj = myQueueCreate();
* myQueuePush(obj, x);
* int param_2 = myQueuePop(obj);
* int param_3 = myQueuePeek(obj);
* bool param_4 = myQueueEmpty(obj);
* myQueueFree(obj);
*/
// 创建队列
typedef struct {
int head;
int tail;
int data[100001];
} MyQueue;
void myQueueInit(MyQueue * obj) {
obj->head = 0;
obj->tail = -1;
}
void myQueuePush(MyQueue * obj, int x) {
obj->data[++obj->tail] = x;
}
int myQueuePop(MyQueue * obj) {
return obj->data[obj->head++];
}
int myQueueTop(MyQueue * obj) {
return obj->data[obj->head];
}
int myQueueSize(MyQueue * obj) {
return obj->tail - obj->head + 1;
}
typedef struct {
MyQueue q[2];
int pushIdx;
} MyStack;
MyStack* myStackCreate() {
MyStack * obj = (MyStack *)malloc( sizeof(MyStack) );
for(int i = 0; i < 2; i++) {
myQueueInit( &obj->q[i]);
}
obj->pushIdx = 0;
return obj;
}
void myStackPush(MyStack* obj, int x) {
MyQueue * q = &(obj->q[obj->pushIdx]);
myQueuePush( q, x);
}
int myStackPop(MyStack* obj) {
MyQueue * pushq = &(obj->q[obj->pushIdx]);
MyQueue * emptyq = &(obj->q[1 - obj->pushIdx]);
while( myQueueSize(pushq) > 1 ) {
myQueuePush(emptyq, myQueuePop(pushq));
}
int ret = myQueuePop(pushq);
obj->pushIdx = 1 - obj->pushIdx;
return ret;
}
int myStackTop(MyStack* obj) {
MyQueue * pushq = &(obj->q[obj->pushIdx]);
MyQueue * emptyq = &(obj->q[1 - obj->pushIdx]);
while( myQueueSize(pushq) > 1 ) {
myQueuePush(emptyq, myQueuePop(pushq));
}
int ret = myQueuePop(pushq);
myQueuePush(emptyq, ret);
obj->pushIdx = 1 - obj->pushIdx;
return ret;
}
bool myStackEmpty(MyStack* obj) {
return myQueueSize(&(obj->q[obj->pushIdx])) == 0;
}
void myStackFree(MyStack* obj) {
free(obj);
}
/**
* Your MyStack struct will be instantiated and called as such:
* MyStack* obj = myStackCreate();
* myStackPush(obj, x);
* int param_2 = myStackPop(obj);
* int param_3 = myStackTop(obj);
* bool param_4 = myStackEmpty(obj);
* myStackFree(obj);
*/