文章作者：Tyan
部落格：noahsnail.com  |  CSDN  |  簡書

1. Description

2. Solution

• Version 1

class Solution {
public:
    bool find132pattern(vector<int>& nums) {
        int size = nums.size();
        if(size == 0) {
            return false;
        }
        int min = nums[0];
        for(int j = 1; j < size - 1; j++) {
            if(nums[j] > min) {
                for(int k = j + 1; k < size; k++) {
                    if(nums[j] > nums[k] && min < nums[k]) {
                        return true;
                    }
                }
            }
            else {
                min = nums[j];
            }
        }
        return false;
    }
};
 

• Version 2

class Solution {
public:
    bool find132pattern(vector<int>& nums) {
        int third = INT_MIN;
        stack<int> s;
        for(int i = nums.size() - 1; i >= 0; i--) {
            if(nums[i] < third) {
                return true;
            } 
            while(!s.empty() && nums[i] > s.top()) {
                third = s.top();
                s.pop();
            }
            s.push(nums[i]);
        }
        return false;
    }
};
 

Reference