题目：

题解：

class Solution {
public:bool find132pattern(vector<int>& nums) {int n = nums.size();vector<int> candidate_i = {nums[0]};vector<int> candidate_j = {nums[0]};for (int k = 1; k < n; ++k) {auto it_i = upper_bound(candidate_i.begin(), candidate_i.end(), nums[k], greater<int>());auto it_j = lower_bound(candidate_j.begin(), candidate_j.end(), nums[k], greater<int>());if (it_i != candidate_i.end() && it_j != candidate_j.begin()) {int idx_i = it_i - candidate_i.begin();int idx_j = it_j - candidate_j.begin() - 1;if (idx_i <= idx_j) {return true;}}if (nums[k] < candidate_i.back()) {candidate_i.push_back(nums[k]);candidate_j.push_back(nums[k]);}else if (nums[k] > candidate_j.back()) {int last_i = candidate_i.back();while (!candidate_j.empty() && nums[k] > candidate_j.back()) {candidate_i.pop_back();candidate_j.pop_back();}candidate_i.push_back(last_i);candidate_j.push_back(nums[k]);}}return false;}
};