leetcode1574

双指针法，结果只能从最左边或者最右边或者最左边加上最右边中取

class Solution {
public:
    int findLengthOfShortestSubarray(vector<int>& arr) {
        int n = arr.size(),res = 1,res2 = 1,res3 = 1,p = n-1,q = 0;
        for(int i=1;i<n;i++){
            if(arr[i]<arr[i-1]){
                p = i-1;
                break;
            }
        }
        if(p==n-1)return 0;
        for(int i=n-1;i>0;i--){
            if(arr[i]<arr[i-1]){
                q = i;
                break;
            }
        }
        int i = 0,j = q;
        while(i<=p&&j<=n-1){
            if(arr[i]<=arr[j]){
                res = max(res,i+1+n-j);
                i++;
            }else{
                j++;
            }
        }
        res3 = n-res;
        res = n-(p+1);
        res2 = n-(n-q);
        return min(min(res,res2),res3);
    }
};