A. Telephone Number

Posted 2021-12-02 ydddd

链接：https://codeforces.com/contest/1167/problem/A

题意：

A telephone number is a sequence of exactly 11 digits, where the first digit is 8. For example, the sequence 80011223388 is a telephone number, but the sequences 70011223388and 80000011223388 are not.

You are given a string ss of length nn, consisting of digits.

In one operation you can delete any character from string ss. For example, it is possible to obtain strings 112, 111 or 121 from string 1121.

You need to determine whether there is such a sequence of operations (possibly empty), after which the string ss becomes a telephone number.

思路：

找到第一个8出现的位置。再把多余的减掉看是否符合。

代码：

#include <bits/stdc++.h>
using namespace std;

typedef long long LL;
const int MAXN = 1e5+10;

int main()
{
    int t;
    cin >> t;
    while (t--)
    {
        int n;
        string s;
        cin >> n >> s;
        int cnt = -1;
        for (int i = 0;i < s.length();i++)
        {
            if (s[i] == ‘8‘)
            {
                cnt = i;
                break;
            }
        }
        if (cnt == -1)
            cout << "NO" << endl;
        else if (s.length() - cnt < 11)
            cout << "NO" << endl;
        else
            cout << "YES" << endl;
    }

    return 0;
}