代码随想录一刷day58

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前言

一、力扣739. 每日温度

class Solution {
    public int[] dailyTemperatures(int[] temperatures) {
        int n = temperatures.length;
        int[] answer = new int[n];
        Deque<Integer> deq = new LinkedList<>();
        deq.push(0);
        for(int i=1; i < n; i ++){
            if(temperatures[i] <= temperatures[deq.peek()]){
                deq.push(i);
            }else {
                while(!deq.isEmpty() && temperatures[i]>temperatures[deq.peek()]){
                    answer[deq.peek()] = i - deq.peek();
                    deq.pop();
                }
                deq.push(i);
            }
        }
        return answer;
    }
}

二、力扣496.下一个更大元素 I

class Solution {
    public int[] nextGreaterElement(int[] nums1, int[] nums2) {
        int n1 = nums1.length;
        int n2 = nums2.length;
        int[] ans = new int[n1];
        Arrays.fill(ans, -1);
        Deque<Integer> deq = new LinkedList<>();
        HashMap<Integer, Integer> hashMap = new HashMap<>();
        deq.push(nums2[0]);
        for(int i = 0; i < n1; i ++){
            hashMap.put(nums1[i], i);
        }
        for(int j = 1; j < n2; j ++){
            if(nums2[j] <= deq.peek()){
                deq.push(nums2[j]);
            }else{
                while(!deq.isEmpty() && nums2[j] > deq.peek()){
                    if(hashMap.containsKey(deq.peek())){
                        int index = hashMap.get(deq.peek());
                        ans[index] = nums2[j];
                    }
                    deq.pop();
                }
                deq.push(nums2[j]);
            }
        }
        return ans;
    }