leetcode-155-Min Stack

                                                   Min Stack

 

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.

 

模拟一个栈，能取出其中的最小元素。

typedef struct {
    int* a;
    int top;
    int maxSize;
} MinStack;

void minStackCreate(MinStack *stack, int maxSize) {
    stack->a = (int*)malloc(sizeof(int)*maxSize);
    stack->top = 0;
    stack->maxSize = maxSize;
}

void minStackPush(MinStack *stack, int element) {
    stack->a[stack->top++] = element;
}

void minStackPop(MinStack *stack) {
    stack->top--;
}

int minStackTop(MinStack *stack) {
    return stack->a[stack->top - 1];
}

int minStackGetMin(MinStack *stack) {
    int minimum = stack->a[0];
    for (int i = 0;i < stack->top;i++){
        if (minimum > stack->a[i]){
            minimum = stack->a[i];
        }
    }
    return minimum;
}

void minStackDestroy(MinStack *stack) {
    free(stack->a);
}