编程习题—— Min Stack

编程习题—— Min Stack。原题：

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• getMin() -- Retrieve the minimum element in the stack.

  Example:

  MinStack minStack = new MinStack();
  minStack.push(-2);
  minStack.push(0);
  minStack.push(-3);
  minStack.getMin();   --> Returns -3.
  minStack.pop();
  minStack.top();      --> Returns 0.
  minStack.getMin();   --> Returns -2.

  
  

  代码如下：

  typedef struct {
      int* intStack;
      int top;
      int max;
  } MinStack;
  
  /** initialize your data structure here. */
  MinStack* minStackCreate(int maxSize) {
      MinStack* testStack;
      testStack=(MinStack*)malloc(sizeof(MinStack));
      testStack->top=-1;
      testStack->max=maxSize;
      testStack->intStack=(int*)malloc(sizeof(int)*maxSize);
      return testStack;
  }
  
  void minStackPush(MinStack* obj, int x) {
      obj->top+=1;
      *(obj->intStack+obj->top)=x;
  }
  
  void minStackPop(MinStack* obj) {
      obj->top-=1;
  }
  
  int minStackTop(MinStack* obj) {
      return *(obj->intStack+obj->top);
  }
  
  int minStackGetMin(MinStack* obj) {
      int min=INT_MAX;
      for(int n=0;n<=obj->top;n++)
      {
          if(*(obj->intStack+n)intStack+n);
          }
      }
      return min;
  }
  
  void minStackFree(MinStack* obj) {
      free(obj->intStack);
      free(obj);
  }
  
  /**
   * Your MinStack struct will be instantiated and called as such:
   * struct MinStack* obj = minStackCreate(maxSize);
   * minStackPush(obj, x);
   * minStackPop(obj);
   * int param_3 = minStackTop(obj);
   * int param_4 = minStackGetMin(obj);
   * minStackFree(obj);
   */