http://codeforces.com/problemset/problem/946/C
You are given a string s consisting of |s| small english letters.
In one move you can replace any character of this string to the next character in alphabetical order (a will be replaced with b, s will be replaced with t, etc.). You cannot replace letter z with any other letter.
Your target is to make some number of moves (not necessary minimal) to get string abcdefghijklmnopqrstuvwxyz (english alphabet) as a subsequence. Subsequence of the string is the string that is obtained by deleting characters at some positions. You need to print the string that will be obtained from the given string and will be contain english alphabet as a subsequence or say that it is impossible.
The only one line of the input consisting of the string s consisting of |s| (1 ≤ |s| ≤ 105) small english letters.
If you can get a string that can be obtained from the given string and will contain english alphabet as a subsequence, print it. Otherwise print «-1» (without quotes).
aacceeggiikkmmooqqssuuwwyy
abcdefghijklmnopqrstuvwxyz
thereisnoanswer
-1
mmp，题意看半天没看懂。。。
题意就是通过使用魔法（可将小字母变大），从字符串中抽取26个字母使其组成连续26英文字母
// 去吧！皮卡丘! 把AC带回来！
// へ ／|
// /＼7 ∠＿/
// / │ ／ ／
// │ Z ＿,＜ ／ /`ヽ
// │ ヽ / 〉
// Y ` / /
// ｲ● ､ ● ⊂⊃〈 /
// () へ | ＼〈
// >ｰ ､_ ィ │ ／／
// / へ / ﾉ＜| ＼＼
// ヽ_ﾉ (_／ │／／
// 7 |／
// ＞―r￣￣`ｰ―＿
//**************************************
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define inf 2147483647
const ll INF = 0x3f3f3f3f3f3f3f3fll;
#define ri register int
template <class T> inline T min(T a, T b, T c) { return min(min(a, b), c); }
template <class T> inline T max(T a, T b, T c) { return max(max(a, b), c); }
template <class T> inline T min(T a, T b, T c, T d) {
return min(min(a, b), min(c, d));
}
template <class T> inline T max(T a, T b, T c, T d) {
return max(max(a, b), max(c, d));
}
#define scanf1(x) scanf("%d", &x)
#define scanf2(x, y) scanf("%d%d", &x, &y)
#define scanf3(x, y, z) scanf("%d%d%d", &x, &y, &z)
#define scanf4(x, y, z, X) scanf("%d%d%d%d", &x, &y, &z, &X)
#define pi acos(-1)
#define me(x, y) memset(x, y, sizeof(x));
#define For(i, a, b) for (int i = a; i <= b; i++)
#define FFor(i, a, b) for (int i = a; i >= b; i--)
#define bug printf("***********\n");
#define mp make_pair
#define pb push_back
const int maxn = 1e8 + ;
const int maxx = 1e6 + ;
// name*******************************
char s[maxn];
// function****************************** //***************************************
int main() {
// ios::sync_with_stdio(0); cin.tie(0);
// freopen("test.txt", "r", stdin);
// freopen("outout.txt","w",stdout);
scanf("%s", s);
int len = strlen(s);
if (len < ) {
cout << -;
return ;
}
int p=;
For(i,,len-){
if(p==)break;
if(s[i]<=p+'a'){
s[i]=p+'a';
p++;
}
}
if(p==)
printf("%s",s );
else
cout<<-; return ;
}