leetcode-225. 用队列实现栈-C语言

#define LEN 0xfffff

typedef struct {
    int *q1, head1, rear1;
    int *q2, head2, rear2;
} MyStack;

/** Initialize your data structure here. */

MyStack* myStackCreate() {
    MyStack* stack = (MyStack * )malloc(sizeof(MyStack));
    stack->q1  = (int *)malloc(sizeof(int) * LEN);
    stack->q2  = (int *)malloc(sizeof(int) * LEN);
    stack->head1 = 0;
    stack->rear1 = 0;
    stack->head2 = 0;
    stack->rear2 = 0;

    return stack;
}

void print(MyStack *obj){
    return;
    int i, j;
    for(i=obj->rear1; ihead1; i++){
        printf("%d,", obj->q1[i]);
    }
    printf("\n");

    for(i=obj->rear2; ihead2; i++){
        printf("%d,", obj->q2[i]);
    }
    printf("\n");

}

/** Push element x onto stack. */
void myStackPush(MyStack* obj, int x) {

    
  if(obj->head1 - obj->rear1 > 0 || (obj->head1 - obj->rear1 == 0 && (obj->head2 - obj->rear2 == 0))){
      obj->q1[obj->head1++] = x;
  }
    
  if(obj->head2 - obj->rear2 > 0){
      obj->q2[obj->head2++] = x;
  }

    print(obj);
}

/** Removes the element on top of the stack and returns that element. */
int myStackPop(MyStack* obj) {
    int ret  = 999;
  if(obj->head2-obj->rear2 > 0){
      while(obj->head2-obj->rear2 > 1){
          obj->q1[obj->head1++] = obj->q2[obj->rear2++];
      }
      
      ret = obj->q2[obj->rear2++];
      goto RET;
  }
    
    if(obj->head1 - obj->rear1 > 0) {
        while(obj->head1 - obj->rear1 > 1) {
            obj->q2[obj->head2++] = obj->q1[obj->rear1++];
        }
        ret =  obj->q1[obj->rear1++];
    }
    
    RET:
    
    print(obj);
    
    return ret;
}

/** Get the top element. */
int myStackTop(MyStack* obj) {
    int ret =   myStackPop(obj);

    myStackPush(obj, ret);
    print(obj);
    return ret;
}

/** Returns whether the stack is empty. */
bool myStackEmpty(MyStack* obj) {
  if(obj->rear1>=obj->head1 && obj->rear2>=obj->head2)
      return true;
    return false;
}

void myStackFree(MyStack* obj) {
    free(obj->q1);
    free(obj->q2);
    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);
*/