#include <iostream>using namespace std;int DoubleEndLIS(int *arr, int len)
{int *LIS = new int[len];int *lefToRight = new int[len];        //leftToRight[i]表示0~i最长子序列长度-1int *rightToLeft = new int[len];int maxLen = 0;        //记录总共的(上升+下降)最长子序列长度int low, high, mid;for (int i = 0; i < len; ++i){lefToRight[i]  = 0;LIS[i] = 0;}LIS[0] = arr[0];for (int i = 1; i < len; i++){low = 0; high = lefToRight[i-1];while (low <= high){mid = (low + high)/2;if (LIS[mid] < arr[i]){low = mid + 1;} else{high = mid -1;}}LIS[low] = arr[i];if (low > lefToRight[i-1]){lefToRight[i] = lefToRight[i-1] + 1;    //最长子序列长度加1
        }else{lefToRight[i] = lefToRight[i-1];}}//leftToRight的每个值增加1，因为他们是最长子序列值-1//此时leftToRight表示的是最长子序列的真正值。for (int i = 0; i < len; i++){lefToRight[i]++;}//从右到左for (int i = 0; i < len; i++){rightToLeft[i] = 0;LIS[i] = 0;}int k = 0;LIS[0] = arr[len-1];for (int i = len -2; i >= 0; --i){low = 0; high = rightToLeft[k];while (low <= high){mid = (low + high)/2;if (LIS[mid] < arr[i]){low = mid + 1;} else{high = mid - 1;}}LIS[low] = arr[i];if (low > rightToLeft[k]){rightToLeft[k+1] = rightToLeft[k] + 1;}else{rightToLeft[k+1] = rightToLeft[k];}++k;}for (int i = 0; i < k; ++i){rightToLeft[i]++;}//求最大值即为要求的for (int i = 0; i < len; ++i){cout<<"i: "<<i<<" "<<lefToRight[i]<<"  "<<rightToLeft[len-i-1]<<endl;if (lefToRight[i] + rightToLeft[len-i-1] > maxLen)maxLen = lefToRight[i] + rightToLeft[len-i-1];}cout<<"maxLen:"<<maxLen<<endl;delete LIS;delete lefToRight;delete rightToLeft;return len - maxLen + 1;
}int main()
{int arr[] = {1,5,7,6,9,3,8,4,2};int ret;ret = DoubleEndLIS(arr, 9);cout<<ret<<endl;return 0;
}