最小栈#155

push(x) -- 将元素 x 推入栈中。
pop() -- 删除栈顶的元素。
top() -- 获取栈顶元素。
getMin() -- 检索栈中的最小元素。 示例:

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

typedef struct {
   
    int top;
    int minTop;
    int *data;
    int *min;
} MinStack;

/** initialize your data structure here. */
MinStack* minStackCreate(int maxSize) {
    MinStack *stack = (MinStack*)malloc(maxSize*sizeof(MinStack));
    stack->data = (int*)malloc(maxSize *sizeof(int));
    stack->min = (int*)malloc(maxSize *sizeof(int));
    // memset(stack->data,0,maxSize);
    // memset(stack->min,0,maxSize);
    stack->top = -1;
    stack->minTop = -1;
    return stack;
}

void minStackPush(MinStack* obj, int x) {
    obj->top++;
    obj->data[obj->top] = x;
    if(obj->minTop == -1 || obj->min[obj->minTop] >= x) {
        obj->minTop++;
        obj->min[obj->minTop] = x;
    }
}

void minStackPop(MinStack* obj) {
    int temp, temp1;
    if(obj->top == -1){
        return;
    }
    temp = obj->data[obj->top];
    obj->top--;
    if(temp == obj->min[obj->minTop]){
       temp1 = obj->min[obj->minTop];
       obj->minTop--;
    }
}

int minStackTop(MinStack* obj) {
   return obj->data[obj->top];
}

int minStackGetMin(MinStack* obj) {
    return obj->min[obj->minTop];
}

void minStackFree(MinStack* 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);
 */