Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		n := io.NextInt()
		if n == 0 {
			break
		}
		k := make([]int, n)
		for i := 0; i < n; i++ {
			k[i] = io.NextInt()
		}
		const st = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
		s := io.NextLine()
		for i, cnt := 0, 0; i < len(s); i, cnt = i+1, (cnt+1)%n {
			idx := strings.IndexRune(st, rune(s[i]))
			c := st[(idx-k[cnt]+52)%52]
			io.Printf("%c", c)
		}
		io.Println()
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

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

typedef ostringstream OSS; typedef istringstream ISS;
typedef long long LL;
typedef pair<int, int> PII;  typedef pair<LL, LL> PLL;
typedef vector<int>    VI;   typedef vector<VI>   VVI;   typedef vector<VVI>   VVVI;
typedef vector<LL>     VLL;  typedef vector<VLL>  VVLL;  typedef vector<VVLL>  VVVLL;
typedef vector<double> VD;   typedef vector<VD>   VVD;   typedef vector<VVD>   VVVD;
typedef vector<string> VS;   typedef vector<VS>   VVS;   typedef vector<VVS>   VVVS;
typedef vector<bool>   VB;   typedef vector<VB>   VVB;   typedef vector<VVB>   VVVB;
typedef vector<PII>    VPII; typedef vector<VPII> VVPII; typedef vector<VVPII> VVVPII;
typedef vector<PLL>    VPLL; typedef vector<VPLL> VVPLL; typedef vector<VVPLL> VVVPLL;

typedef unsigned int  UI;
typedef vector<UI>    VUI;
typedef vector<VUI>   VVUI;

#define fst first
#define snd second
// #define Y first
// #define X second
#define MP make_pair
#define PB push_back
#define EB emplace_back 
#define ALL(x)  (x).begin(),(x).end()
#define RALL(x) (x).rbegin(),(x).rend()
#define RANGEBOX(x,y,maxX,maxY) (0 <= (x) && 0 <= (y) && (x) < (maxX) && (y) < (maxY))
#define RANGE(x, l, r) ((l) <= (x) && (x) <= (r))
#define rep(i, N)  for (int i = 0; i < (int)(N); i++)
#define rrep(i, N) for (int i = N - 1; i >= 0; i--)
#define REP(i, init, N)  for (int i = (init); i < (int)(N); i++)
#define RREP(i, N, last) for (int i = (init - 1); i >= last; i--)
#define MAXUD(orig, target) orig = max(orig, target)
#define MINUD(orig, target) orig = min(orig, target)
#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

template < typename T > inline T fromString(const string &s) { T res; ISS iss(s); iss >> res; return res; };
template < typename T > inline string toString(const T &a)   { OSS oss; oss << a; return oss.str(); };

template<typename T=int> inline void dump(vector<T> vs, bool ent=false) { rep(i, vs.size()) cout << vs[i] << (i+1==vs.size() ? '\n' : ' '); if (ent) cout << endl; }
template<typename T = int> inline void dump(vector<vector<T>> vs, bool ent = false) { rep(i, vs.size()) dump<T>(vs[i]); if (ent) cout << endl; }

const int    INF  = 0x3f3f3f3f;
const LL     INFL = 0x3f3f3f3f3f3f3f3fLL;
const double DINF = 0x3f3f3f3f;
const int    DX[] = {1,  0, -1, 0};
const int    DY[] = {0, -1,  0, 1};
const double EPS  = 1e-12;
// const double PI   = acos(-1.0);
// lambda: [](T1 x)->T2{return y;}
// simple lambda: [](T x){return x;}

string S;

string solve(int N) {
    VI ks(N);
    rep(i, N) cin >> ks[i];
    string s;
    cin >> s;

    string ans(s);

    int M = S.size();

    rep(i, s.size()) {
        int p = i % (int)ks.size();
        int pos = find(ALL(S), s[i]) - S.begin();
        int pos2 = (pos - ks[p] + M) % M;
        ans[i] = S[pos2];
    }
    
    return ans;
}

int main(void) {
    rep(i, 26) S += 'a' + i;
    rep(i, 26) S += 'A' + i;

    int N;
    while (cin >> N, N) cout << solve(N) << endl;

    return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <vector>
#include <string>
#include <queue>
#include <algorithm>
#include <math.h>
#include <utility>
#include <set>
#include <map>
#include <cstring>
#include <cstdio>
#include <stack>
#define INF 1000000000
#define rep(i,n) for(int i =0;i<n;i++)
using namespace std;
typedef long long int ll;

char o(int n, char a){
    if(n==0) return a;
    if (a=='a') return o(n-1,'Z');
    if (a=='A') return o(n-1,'z');
    return o(n-1, (char)((int)a-1));
}

int main(){
    for(;;){
        int n;
        cin >>n;
        if(!n)break;
        vector<int> key(n);
        rep(i,n) cin >> key[i];
        string s;
        cin >> s;
        string ans="";
        int j=0;
        for (int i=0; i<s.length(); i++) {
            ans += o(key[j],s[i]);
            j++;
            if(j==key.size()) j=0;
        }
        cout << ans << endl;
    }
}

C++: #include <iostream>
#include <vector>
#include <map>
using namespace std;

int main(){
  int n;
  string A(52,'?');
  for(int i = 0; i < 26; ++i) A[i] = 'a'+i;
  for(int i = 0; i < 26; ++i) A[i+26] = 'A'+i;
  map<char,int> M;
  for(int i = 0; i < 52; ++i) M[A[i]] = i;
  while(cin >> n, n){
    vector<int> K(n);
    for(int i = 0; i < n; ++i) cin >> K[i];
    string s;
    cin >> s;
    for(size_t i = 0; i < s.length(); ++i){
      cout << A[(M[s[i]]+52-K[i%n])%52];
    }
    cout << endl;
  }
}

C++: #include <iostream>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <string>
using namespace std;






int n;
int key[110];
string str;

char x[60];

int main(){
  
  while(1){
    cin >> n;
    if(n == 0) break;

    for(int i= 0; i < n ; i++)
      cin >> key[i];

    cin >> str;

    string a = "a";

    for(int i = 0,j = 0; i < str.size() ; i++,j++){
      if(i % n == 0) j = 0;
      
      char tmp = str[i] - key[j]; 
   
      if(str[i] - key[j] < 'A' ){
	str[i] += 52 + 6;

      }
      if(str[i] > 'a' && str[i] - key[i] < 'a') str[i] -= 6;
      str[i] -= key[j];
    }
      cout << str << endl;
  }



  return 0;
}