Leetcode-403 Frog Jump(青蛙过河)

#define pb push_back
#define _for(i,a,b) for(int i = (a);i < (b);i ++)
class Solution
{
    public:
        bool canCross(vector<int>& stones)
        {
            int sz = stones.size();
            if(sz==2&&stones[1]==1) return true;

            vector<set<int>> dp(sz);
            dp[0].insert(0);
            for(int i = 1; i < sz; i ++)
            {
                int szz = dp[i-1].size();
                cout << szz << endl;
                for(auto j = dp[i-1].begin(); j != dp[i-1].end(); j ++)
                {
                    if(binary_search(stones.begin(),stones.end(),stones[i-1]+*j))
                        dp[lower_bound(stones.begin(),stones.end(),stones[i-1]+*j)-stones.begin()].insert(*j);
                    if(binary_search(stones.begin(),stones.end(),stones[i-1]+*j+1))
                        dp[lower_bound(stones.begin(),stones.end(),stones[i-1]+*j+1)-stones.begin()].insert(*j+1);
                    if(*j!=1&&binary_search(stones.begin(),stones.end(),stones[i-1]+*j-1))
                        dp[lower_bound(stones.begin(),stones.end(),stones[i-1]+*j-1)-stones.begin()].insert(*j-1);
                }
            }
            if(dp[sz-1].empty())
                return false;
            return true;
        }
};