Problem p00467 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common

typedef int i32;
typedef long long i64, ll;
typedef long double ld;

#define BR "\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define FOR(i, l, r) for (int i = (int)l; i < (int)(r); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #define NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \
  if (exp != act) {                                                            \
    DUMPLN(exp);                                                               \
    DEBUGLN(act);                                                              \
  }
#define STOP(e)                                                                \
  CHECK(e, true);                                                              \
  if (!(e))                                                                    \
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

string BITtoString(int bit) {
  stringstream ss;
  while (bit != 0) {
    ss << (bit % 2);
    bit /= 2;
  }
  string res = ss.str();
  reverse(ALL(res));
  return res;
}

template <typename T, typename V> inline T pmod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
#define nextInt(n) scanf("%d", &n)
#define defInt(n)                                                              \
  int n;                                                                       \
  nextInt(n)
#define nextLong(n) scanf("%lld", &n)
#define defLong(n)                                                             \
  ll n;                                                                        \
  nextLong(n)
#define nextDouble(n) scanf("%lf", &n)

struct UnionFind {
  vector<int> par;  // 親
  vector<int> rank; // 木の深さ
  vector<int> ss;   // xの属する集合のサイズ:option
  int size;         // 集合の個数:option
  UnionFind(int n) {
    REP(i, n) par.push_back(i);
    rank = vector<int>(n);
    ss = vector<int>(n, 1);
    size = n;
  }
  int root(int x) {
    if (par[x] == x)
      return x;
    return par[x] = root(par[x]);
  }
  bool same(int x, int y) { return root(x) == root(y); }
  void unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return;
    if (rank[x] < rank[y]) {
      par[x] = y;
      ss[y] += ss[x];
    } else {
      par[y] = x;
      ss[x] += ss[y];
    }
    if (rank[x] == rank[y])
      rank[x]++;
    size--;
  }
};

namespace SpanningTree {
typedef double Cost;
struct Edge {
  int from, to;
  Cost cost;
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost){};

  bool operator<(Edge r) const { return cost < r.cost; }
  bool operator>(Edge r) const { return cost > r.cost; }
};
typedef vector<vector<Edge>> Graph;

// O(E*log(V))
//  verified by ACAC002 B
//  http://judge.u-aizu.ac.jp/onlinejudge/creview.jsp?rid=899132&cid=ACAC002
Cost kruskal(Graph g) {
  const int V = g.size();
  UnionFind uf = UnionFind(V);
  priority_queue<Edge, vector<Edge>, greater<Edge>> que;
  REP(u, V) for (Edge e : g[u]) que.push(e);
  Cost res = 0;
  while (!que.empty()) {
    Edge e = que.top();
    que.pop();
    if (!uf.same(e.from, e.to)) {
      uf.unite(e.from, e.to);
      res += e.cost;
    }
  }
  return res;
}
} // namespace SpanningTree
using namespace SpanningTree;

class Main {
public:
  void run() {
    //	ifstream cin("in");
    //	ofstream cout( "out" );
    while (true) {
      int N, M;
      nextInt(N);
      nextInt(M);
      if (N == 0 && M == 0)
        break;
      vector<int> as(N);
      REP(i, N) nextInt(as[i]);

      vector<int> bs(M);
      REP(i, M) nextInt(bs[i]);
      int pos = 0;
      REP(j, M) {
        pos += bs[j];
        if (pos >= N - 1) {
          cout << (j + 1) << endl;
          break;
        }
        pos += as[pos];
        if (pos >= N - 1) {
          cout << (j + 1) << endl;
          break;
        }
        DUMP(pos);
      }
    }
  }
};
int main() {
  cout << fixed << setprecision(13);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}

Fixed submission:
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common

typedef int i32;
typedef long long i64, ll;
typedef long double ld;

#define BR "\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define FOR(i, l, r) for (int i = (int)l; i < (int)(r); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #define NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \
  if (exp != act) {                                                            \
    DUMPLN(exp);                                                               \
    DEBUGLN(act);                                                              \
  }
#define STOP(e)                                                                \
  CHECK(e, true);                                                              \
  if (!(e))                                                                    \
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

string BITtoString(int bit) {
  stringstream ss;
  while (bit != 0) {
    ss << (bit % 2);
    bit /= 2;
  }
  string res = ss.str();
  reverse(ALL(res));
  return res;
}

template <typename T, typename V> inline T pmod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
#define nextInt(n) scanf("%d", &n)
#define defInt(n)                                                              \
  int n;                                                                       \
  nextInt(n)
#define nextLong(n) scanf("%lld", &n)
#define defLong(n)                                                             \
  ll n;                                                                        \
  nextLong(n)
#define nextDouble(n) scanf("%lf", &n)

struct UnionFind {
  vector<int> par;  // 親
  vector<int> rank; // 木の深さ
  vector<int> ss;   // xの属する集合のサイズ:option
  int size;         // 集合の個数:option
  UnionFind(int n) {
    REP(i, n) par.push_back(i);
    rank = vector<int>(n);
    ss = vector<int>(n, 1);
    size = n;
  }
  int root(int x) {
    if (par[x] == x)
      return x;
    return par[x] = root(par[x]);
  }
  bool same(int x, int y) { return root(x) == root(y); }
  void unite(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y)
      return;
    if (rank[x] < rank[y]) {
      par[x] = y;
      ss[y] += ss[x];
    } else {
      par[y] = x;
      ss[x] += ss[y];
    }
    if (rank[x] == rank[y])
      rank[x]++;
    size--;
  }
};

namespace SpanningTree {
typedef double Cost;
struct Edge {
  int from, to;
  Cost cost;
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost){};

  bool operator<(Edge r) const { return cost < r.cost; }
  bool operator>(Edge r) const { return cost > r.cost; }
};
typedef vector<vector<Edge>> Graph;

// O(E*log(V))
//  verified by ACAC002 B
//  http://judge.u-aizu.ac.jp/onlinejudge/creview.jsp?rid=899132&cid=ACAC002
Cost kruskal(Graph g) {
  const int V = g.size();
  UnionFind uf = UnionFind(V);
  priority_queue<Edge, vector<Edge>, greater<Edge>> que;
  REP(u, V) for (Edge e : g[u]) que.push(e);
  Cost res = 0;
  while (!que.empty()) {
    Edge e = que.top();
    que.pop();
    if (!uf.same(e.from, e.to)) {
      uf.unite(e.from, e.to);
      res += e.cost;
    }
  }
  return res;
}
} // namespace SpanningTree
using namespace SpanningTree;

class Main {
public:
  void run() {
    //	ifstream cin("in");
    //	ofstream cout( "out" );
    while (true) {
      int N, M;
      nextInt(N);
      nextInt(M);
      if (N == 0 && M == 0)
        break;
      vector<int> as(N);
      REP(i, N) nextInt(as[i]);

      vector<int> bs(M);
      REP(i, M) nextInt(bs[i]);
      int pos = 0;
      REP(j, M) {
        pos += bs[j];
        if (pos >= N - 1) {
          cout << (j + 1) << endl;
          break;
        }
        pos += as[pos];
        if (pos >= N - 1) {
          cout << (j + 1) << endl;
          break;
        }
      }
    }
  }
};
int main() {
  cout << fixed << setprecision(13);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}