Get min Len of unsorted arr's subarr

 需要排序的最短子数组长度
 给定一个无序数组，求出需要返回的最短子数组的长度
 arr = [1, 5, 3, 4, 6, 7]   [5, 3, 4, 2]

#include <vector>
#include <iostream>
using namespace std;

int getMinLen(vector<int> &arr){
    int n = arr.size();

    if(n <= 0) return 0;

    int minNum = arr[n - 1];
    int minIndex = -1;
    for(int i = n - 2; i >= 0; i--){
        if(arr[i] > minNum){
            minIndex = i;
        }else{
            minNum = min(minNum, arr[i]);
        }
    }

    if(minIndex == -1)  return 0;

    int maxNum = arr[0];
    int maxIndex = -1;

    for(int i = 1; i <= n-1; i++){
        if(arr[i] < maxNum){
            maxIndex = i;
        }else{
            maxNum = max(maxNum, arr[i]);
        }
    }

    return maxIndex - minIndex + 1;
}

int main(){
    vector<int> test ={1 ,5, 3, 4, 2, 8, 7};

    cout<<getMinLen(test)<<endl;

    return 0;
}