最长准恒子序列

#include <iostream>
#include <vector>
#include <math.h>
using namespace std;

bool ok(vector<int> &A)
{
	int n = A.size();
	if(n < 2)
		return true;

	int max = A[0];
	int min = A[0];
	for(int i=1; i<n; i++)
	{
		if(max < A[i])
			max = A[i];
		if(min > A[i])
			min = A[i];
	}
	return abs(max - min)<2;
}

int maxSum = 0;

void dfs(int dep, int n, vector<int> &A, vector<int> &tmp)
{
	if(dep >= n)
	{
		if(ok(tmp) && tmp.size() > maxSum)
			maxSum = tmp.size();
		return;
	}
	
	tmp.push_back(A[dep]);
	dfs(dep+1, n, A, tmp);
	tmp.pop_back();
	dfs(dep+1, n, A, tmp);
}

int solution(vector<int> &A)
{
	int n = A.size();
	if(n < 1)
		return 1;

	vector<int> tmp;
	dfs(0, n, A, tmp);
	return maxSum;
}

int main() 
{
  vector<int> a;
  a.push_back(6);
  a.push_back(10);
  a.push_back(6);
  a.push_back(9);
  a.push_back(7);
  a.push_back(8);
  cout << solution(a) << endl;
  getchar();
  getchar();
}