常用算法

1.判断回文数

bool check(vector<int> A)
{
    for (int i = 0, j = A.size() - 1; i < j; i ++, j -- )
        if (A[i] != A[j])
            return false;
    return true;
}

2.计算排名

    sort(schools.begin(), schools.end(), cmp);
    int rank = 1;
    for (int i = 0; i < schools.size(); i ++ )
    {
        if (i && schools[i].sum != schools[i - 1].sum) rank = i + 1;
        schools[i].rank=rank;
    }

3.多关键字排序

bool cmp(Stu a, Stu b)
{
    if (a.name != b.name) return a.name < b.name;
    return a.id < b.id;
}