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leetcode155-最小棧

typedef struct {
    int *top;
    int *base;
    int statckSize;
    
} MinStack;

/** initialize your data structure here. */
MinStack* minStackCreate(int maxSize) {
    MinStack *stack = (MinStack*)malloc(sizeof(MinStack));
    stack->base = (int*)malloc(maxSize*sizeof(int));
    stack->top = stack->base
; stack->statckSize = maxSize; return stack; } void minStackPush(MinStack* obj, int x) { if(obj->top - obj->base <= obj->statckSize) { *(obj->top) = x; obj->top++; } else { exit(1); } } void minStackPop(MinStack* obj) {
if(obj->top != obj->base) { obj->top--; } else { exit(1); } } int minStackTop(MinStack* obj) { return *(obj->top); } int minStackGetMin(MinStack* obj) { int min; int *top = obj->top; int *base = obj->base; min = *top; while
((top--) != base) { if(*top < min) min = *top; } return min; } void minStackFree(MinStack* obj) { free(obj->base); free(obj); }

設計一個支援 push,pop,top 操作,並能在常數時間內檢索到最小元素的棧。

  • push(x) -- 將元素 x 推入棧中。
  • pop() -- 刪除棧頂的元素。
  • top() -- 獲取棧頂元素。
  • getMin() -- 檢索棧中的最小元素。

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.