DP(3)

LeetCode #135

int candy(vector<int> &ratings) {
    int len = ratings.size();
    vector<int> candy_vec(len);


    //初始化
    for (auto &i : candy_vec)
        i = 1;
    //left -> right
    for (int i = 1; i < len; i++)
    {
        if (ratings[i] > ratings[i - 1] && candy_vec[i] <= candy_vec[i - 1])
            candy_vec[i] = candy_vec[i - 1] + 1;
    }

    //right -> left
    for (int i = len - 2; i >= 0; i--)
    {
        if (ratings[i] > ratings[i + 1]&&candy_vec[i]<=candy_vec[i+1])
            candy_vec[i] = candy_vec[i + 1] + 1;
    }

    int sum = 0;
    for (auto i : candy_vec)
        sum += i;

    return sum;
}