class Solution {
public:vector<int> dailyTemperatures(vector<int>& temperatures) {vector<int> rst(temperatures.size());vector<int> decsStk; // 单调递减栈for (int i = 0; i < temperatures.size(); i++){while (!decsStk.empty() && temperatures[decsStk.back()] < temperatures[i]){rst[decsStk.back()] = i - decsStk.back();decsStk.pop_back();}decsStk.push_back(i);}return rst;}
};

class Solution {
public:vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) {vector<int> decsStk; // 存放nums2的下标unordered_map<int, int> table;for (int i = 0; i < nums2.size(); ++i){while (!decsStk.empty() && nums2[decsStk.back()] < nums2[i]){table[nums2[decsStk.back()]] = nums2[i];decsStk.pop_back();}decsStk.push_back(i);}vector<int> rst(nums1.size(), -1);for (int i = 0; i < nums1.size(); i++){if (table.find(nums1[i]) != table.end()){rst[i] = table[nums1[i]];}}return rst;}
};