HDU5842 Lweb and String水题

Posted 2021-01-31 新海岛Blog

Lweb and String

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 2062 Accepted Submission(s): 956

Problem Description
Lweb has a string S.

Oneday, he decided to transform this string to a new sequence.

You need help him determine this transformation to get a sequence which has the longest LIS(Strictly Increasing).

You need transform every letter in this string to a new number.

A is the set of letters of S, B is the set of natural numbers.

Every injection f:A→B can be treat as an legal transformation.

For example, a String “aabc”, A={a,b,c}, and you can transform it to “1 1 2 3”, and the LIS of the new sequence is 3.

Now help Lweb, find the longest LIS which you can obtain from S.

LIS: Longest Increasing Subsequence. (https://en.wikipedia.org/wiki/Longest_increasing_subsequence)

Input
The first line of the input contains the only integer T,(1≤T≤20).

Then T lines follow, the i-th line contains a string S only containing the lowercase letters, the length of S will not exceed 105.

Output
For each test case, output a single line "Case #x: y", where x is the case number, starting from 1. And y is the answer.

Sample Input
2
aabcc
acdeaa

Sample Output
Case #1: 3
Case #2: 4

Author
UESTC

Source
2016中国大学生程序设计竞赛 - 网络选拔赛

问题链接：HDU5842 Lweb and String
问题简述：
????统计不同字母的数量。
问题分析：
????统计问题用个标记数组标记一下出现过的字母就可以了，标记字母的同时进行统计。
程序说明：（略）
参考链接：（略）
题记：（略）

AC的C语言程序如下：

/* HDU5842 Lweb and String */

#include <stdio.h>

#define N 100000
char s[N + 1];

int main(void)
{
    int n, ans, caseno = 0, i;
    scanf("%d", &n);
    while(n--) {
        int flag[26] = {0};
        scanf("%s", s);
        ans = 0;
        for(i = 0; s[i]; i++)
            if(flag[s[i] - 'a'] == 0)
                ans++, flag[s[i] - 'a'] = 1;

        printf("Case #%d: %d
", ++caseno, ans);
    }

    return 0;
}