相似串

题目链接： http://exercise.acmcoder.com/online/online_judge_ques?ques_id=3369&konwledgeId=40

解题思路： 按照题意把每个出现的字符替换掉就可以了。

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 
 4 typedef long long LL;
 5 const int MAXN=100005;
 6 const LL MOD7 = 1e9+7;
 7 
 8 set<char> unseen;
 9 map<char,char> mp;
10 char s[MAXN];
11 void solve()
12 {
13     unseen.clear();
14     for (char ch='a';ch<='z';++ch) unseen.insert(ch);
15     mp.clear();
16     char ch='a';
17     for (int i=0;s[i];++i)
18     {
19         auto it=unseen.find(s[i]);
20         if (it!=unseen.end())
21         {
22             mp[*it]=ch++;
23             unseen.erase(it);
24         }
25         printf("%c",mp[s[i]]);
26     }
27     printf("\n");
28 }
29 int main()
30 {
31 #ifndef ONLINE_JUDGE
32     freopen("test.txt","r",stdin);
33 #endif // ONLINE_JUDGE
34     scanf("%s",s);
35     solve();
36     return 0;
37 }