#define Max_size 10000
//x_stack存储正常入栈元素，min_stack用来存储入栈时栈中最小的元素
//x_top和min_top分别为栈顶的下标
//min_value用来存储最小值
typedef struct {
    int *x_stack;
    int *min_stack;
    int x_top;
    int min_top;
    int min_value;
} MinStack;

/** initialize your data structure here. */

MinStack* minStackCreate() {
    MinStack *obj = (MinStack*)malloc(sizeof(MinStack));
    obj->x_stack = (int*)malloc(sizeof(int) * Max_size);
    obj->min_stack = (int*)malloc(sizeof(int) * Max_size);
    obj->min_top = obj->x_top = -1;
    obj->min_value = 0;
    return obj;
}

void minStackPush(MinStack* obj, int x) {
    if(obj->x_top < Max_size)
    {
        if(obj->x_top == -1)
            obj->min_value = x;
        obj->x_stack[++(obj->x_top)] = x;
        if(x < obj->min_value)
            obj->min_value = x;     //当前元素比min_value小时改变min_value
        obj->min_stack[++(obj->min_top)] = obj->min_value;
    }
}

void minStackPop(MinStack* obj) {
    --(obj->x_top);
    --(obj->min_top);
    if(obj->min_top != -1)
        obj->min_value = obj->min_stack[obj->min_top];//出栈后将min_value变成min_stack的栈顶元素
}

int minStackTop(MinStack* obj) {
    return obj->x_stack[obj->x_top];
}

int minStackMin(MinStack* obj) {
    return obj->min_stack[obj->min_top];
}

void minStackFree(MinStack* obj) {
    free(obj->x_stack);
    free(obj->min_stack);
    free(obj);
}