Codeforces 672

题目链接：http://codeforces.com/contest/672/problem

A. Summer Camp（打表）

题意：123456789...一串字符串，问第n个是什么数字。

塞一个表进去。

/*
━━━━━┒ギリギリ♂ eye！
┓┏┓┏┓┃キリキリ♂ mind！
┛┗┛┗┛┃＼○／
┓┏┓┏┓┃ /
┛┗┛┗┛┃ノ)
┓┏┓┏┓┃
┛┗┛┗┛┃
┓┏┓┏┓┃
┛┗┛┗┛┃
┓┏┓┏┓┃
┛┗┛┗┛┃
┓┏┓┏┓┃
┃┃┃┃┃┃
┻┻┻┻┻┻
*/
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cstring>
#include <climits>
#include <complex>
#include <fstream>
#include <cassert>
#include <cstdio>
#include <bitset>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <ctime>
#include <set>
#include <map>
#include <cmath>
using namespace std;
#define fr first
#define sc second
#define cl clear
#define BUG puts("here!!!")
#define W(a) while(a--)
#define pb(a) push_back(a)
#define Rint(a) scanf("%d", &a)
#define Rll(a) scanf("%I64d", &a)
#define Rs(a) scanf("%s", a)
#define Cin(a) cin >> a
#define FRead() freopen("in", "r", stdin)
#define FWrite() freopen("out", "w", stdout)
#define Rep(i, len) for(int i = 0; i < (len); i++)
#define For(i, a, len) for(int i = (a); i < (len); i++)
#define Cls(a) memset((a), 0, sizeof(a))
#define Clr(a, x) memset((a), (x), sizeof(a))
#define Fuint(a) memset((a), 0x7f7f, sizeof(a))
#define lrt rt << 1
#define rrt rt << 1 | 1
#define pi 3.14159265359
#define RT return
#define lowbit(x) x & (-x)
#define onenum(x) __builtin_popcount(x)
typedef long long LL;
typedef long double LD;
typedef unsigned long long Uint;
typedef pair<int, int> pii;
typedef pair<string, int> psi;
typedef map<string, int> msi;
typedef vector<int> vi;
typedef vector<int> vl;
typedef vector<vl> vvl;
typedef vector<bool> vb;

const int maxn = 100100;
int n;
char s[maxn];
int vis[256];

int main(int argc, char const *argv[]) {
// FRead();
while(~Rint(n)) {
Cls(vis);
Rs(s);
if(n > 26) {
printf("-1\n");
continue;
}
for(int i = 0; s[i]; i++) {
vis[s[i]]++;
}
int ret = 0;
Rep(i, 256) {
if(vis[i] > 1) ret += vis[i] - 1;
}
if(ret > 26) printf("-1\n");
else printf("%d\n", ret);
}
return 0;
}

B