93 lines
2.1 KiB
Java
93 lines
2.1 KiB
Java
//设计一个支持 push ，pop ，top 操作，并能在常数时间内检索到最小元素的栈。
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//
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//
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// push(x) —— 将元素 x 推入栈中。
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// pop() —— 删除栈顶的元素。
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// top() —— 获取栈顶元素。
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// getMin() —— 检索栈中的最小元素。
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//
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//
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//
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//
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// 示例:
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//
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// 输入：
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//["MinStack","push","push","push","getMin","pop","top","getMin"]
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//[[],[-2],[0],[-3],[],[],[],[]]
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//
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//输出：
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//[null,null,null,null,-3,null,0,-2]
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//
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//解释：
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//MinStack minStack = new MinStack();
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//minStack.push(-2);
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//minStack.push(0);
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//minStack.push(-3);
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//minStack.getMin(); --> 返回 -3.
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//minStack.pop();
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//minStack.top(); --> 返回 0.
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//minStack.getMin(); --> 返回 -2.
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//
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//
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//
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//
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// 提示：
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//
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//
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// pop、top 和 getMin 操作总是在 非空栈 上调用。
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//
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// Related Topics 栈 设计
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// 👍 856 👎 0
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package leetcode.editor.cn;
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import java.util.Stack;
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//155:最小栈
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public class MinStack {
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public static void main(String[] args) {
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//测试代码
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// Solution solution = new MinStack().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class MinStack {
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Stack<Integer> stack;
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Stack<Integer> min;
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public MinStack() {
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stack = new Stack<>();
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min = new Stack<>();
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}
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public void push(int val) {
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if (stack.isEmpty()) {
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min.push(val);
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} else {
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min.push(Math.min(min.peek(),val));
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}
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stack.push(val);
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}
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public void pop() {
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stack.pop();
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min.pop();
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}
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public int top() {
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return stack.peek();
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}
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public int getMin() {
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return min.peek();
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}
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}
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/**
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* Your MinStack object will be instantiated and called as such:
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* MinStack obj = new MinStack();
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* obj.push(val);
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* obj.pop();
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* int param_3 = obj.top();
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* int param_4 = obj.getMin();
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*/
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//leetcode submit region end(Prohibit modification and deletion)
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} |