Problem p03176 (C++)

Buggy submission (status: Runtime Error):
/*
    if you can't see the repay
    Why not just work step by step
    rubbish is relaxed
    to ljq
*/
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdlib.h>
#include <vector>
using namespace std;

#define dbg(x) cout << #x << " = " << (x) << endl
#define dbg2(x1, x2)                                                           \
  cout << #x1 << " = " << x1 << " " << #x2 << " = " << x2 << endl
#define dbg3(x1, x2, x3)                                                       \
  cout << #x1 << " = " << x1 << " " << #x2 << " = " << x2 << " " << #x3        \
       << " = " << x3 << endl
#define max3(a, b, c) max(a, max(b, c))
#define min3(a, b, c) min(a, min(b, c))
#define lc (rt << 1)
#define rc (rt << 11)
#define mid ((l + r) >> 1)

typedef pair<int, int> pll;
typedef long long ll;
const int inf = 0x3f3f3f3f;
const int _inf = 0xc0c0c0c0;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const ll _INF = 0xc0c0c0c0c0c0c0c0;
const ll mod = (int)1e9 + 7;

ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll ksm(ll a, ll b, ll mod) {
  int ans = 1;
  while (b) {
    if (b & 1)
      ans = (ans * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return ans;
}
ll inv2(ll a, ll mod) { return ksm(a, mod - 2, mod); }
void exgcd(ll a, ll b, ll &x, ll &y, ll &d) {
  if (!b) {
    d = a;
    x = 1;
    y = 0;
  } else {
    exgcd(b, a % b, y, x, d);
    y -= x * (a / b);
  }
} // printf("%lld*a + %lld*b = %lld\n", x, y, d);
const int MAX_N = 100025;
ll Max(ll a, ll b) {
  if (a > b)
    return a;
  return b;
}
struct node {
  int id, h;
  ll s;
} arr[MAX_N];
ll dp[MAX_N], maxx[MAX_N << 2];
void up(int rt) { maxx[rt] = Max(maxx[rt << 1], maxx[rt << 1 | 1]); }
void update(int rt, int l, int r, int x, ll v) {
  if (l == r) {
    maxx[rt] = Max(maxx[rt], v);
    return;
  }
  if (x <= mid)
    update(rt << 1, l, mid, x, v);
  else
    update(rt << 1 | 1, mid + 1, r, x, v);
  up(rt);
}
ll query(int rt, int l, int r, int x, int y) {
  if (x > r || y < l)
    return 0;
  if (x <= l && r <= y) {
    return maxx[rt];
  }
  if (x > mid)
    return query(rt << 1 | 1, mid + 1, r, x, y);
  else if (y <= mid)
    return query(rt << 1, l, mid, x, y);
  else
    return Max(query(rt << 1, l, mid, x, y),
               query(rt << 1 | 1, mid + 1, r, x, y));
}
int main() {
  // ios::sync_with_stdio(false);
  // freopen("a.txt","r",stdin);
  // freopen("b.txt","w",stdout);
  int n;
  ll ans = 0;
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i)
    scanf("%d", &arr[i].h);
  for (int i = 1; i <= n; ++i)
    scanf("%lld", &arr[i].s), arr[i].id = i;
  for (int i = 1; i <= n; ++i) {
    ll tmp = 0;
    if (arr[i].h > 1)
      tmp = query(1, 1, n, 1, arr[i].h - 1);
    update(1, 1, n, arr[i].h, tmp + arr[i].s);
  }
  printf("%lld\n", maxx[1]);
  // fclose(stdin);
  // fclose(stdout);
  // cout << "time: " << (long long)clock() * 1000 / CLOCKS_PER_SEC << " ms" <<
  // endl;
  return 0;
}


Fixed submission:
/*
    if you can't see the repay
    Why not just work step by step
    rubbish is relaxed
    to ljq
*/
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdlib.h>
#include <vector>
using namespace std;

#define dbg(x) cout << #x << " = " << (x) << endl
#define dbg2(x1, x2)                                                           \
  cout << #x1 << " = " << x1 << " " << #x2 << " = " << x2 << endl
#define dbg3(x1, x2, x3)                                                       \
  cout << #x1 << " = " << x1 << " " << #x2 << " = " << x2 << " " << #x3        \
       << " = " << x3 << endl
#define max3(a, b, c) max(a, max(b, c))
#define min3(a, b, c) min(a, min(b, c))
#define lc (rt << 1)
#define rc (rt << 11)
#define mid ((l + r) >> 1)

typedef pair<int, int> pll;
typedef long long ll;
const int inf = 0x3f3f3f3f;
const int _inf = 0xc0c0c0c0;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const ll _INF = 0xc0c0c0c0c0c0c0c0;
const ll mod = (int)1e9 + 7;

ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll ksm(ll a, ll b, ll mod) {
  int ans = 1;
  while (b) {
    if (b & 1)
      ans = (ans * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return ans;
}
ll inv2(ll a, ll mod) { return ksm(a, mod - 2, mod); }
void exgcd(ll a, ll b, ll &x, ll &y, ll &d) {
  if (!b) {
    d = a;
    x = 1;
    y = 0;
  } else {
    exgcd(b, a % b, y, x, d);
    y -= x * (a / b);
  }
} // printf("%lld*a + %lld*b = %lld\n", x, y, d);
const int MAX_N = 200025;
ll Max(ll a, ll b) {
  if (a > b)
    return a;
  return b;
}
struct node {
  int id, h;
  ll s;
} arr[MAX_N];
ll dp[MAX_N], maxx[MAX_N << 2];
void up(int rt) { maxx[rt] = Max(maxx[rt << 1], maxx[rt << 1 | 1]); }
void update(int rt, int l, int r, int x, ll v) {
  if (l == r) {
    maxx[rt] = Max(maxx[rt], v);
    return;
  }
  if (x <= mid)
    update(rt << 1, l, mid, x, v);
  else
    update(rt << 1 | 1, mid + 1, r, x, v);
  up(rt);
}
ll query(int rt, int l, int r, int x, int y) {
  if (x > r || y < l)
    return 0;
  if (x <= l && r <= y) {
    return maxx[rt];
  }
  if (x > mid)
    return query(rt << 1 | 1, mid + 1, r, x, y);
  else if (y <= mid)
    return query(rt << 1, l, mid, x, y);
  else
    return Max(query(rt << 1, l, mid, x, y),
               query(rt << 1 | 1, mid + 1, r, x, y));
}
int main() {
  // ios::sync_with_stdio(false);
  // freopen("a.txt","r",stdin);
  // freopen("b.txt","w",stdout);
  int n;
  ll ans = 0;
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i)
    scanf("%d", &arr[i].h);
  for (int i = 1; i <= n; ++i)
    scanf("%lld", &arr[i].s), arr[i].id = i;
  for (int i = 1; i <= n; ++i) {
    ll tmp = 0;
    if (arr[i].h > 1)
      tmp = query(1, 1, n, 1, arr[i].h - 1);
    update(1, 1, n, arr[i].h, tmp + arr[i].s);
  }
  printf("%lld\n", maxx[1]);
  // fclose(stdin);
  // fclose(stdout);
  // cout << "time: " << (long long)clock() * 1000 / CLOCKS_PER_SEC << " ms" <<
  // endl;
  return 0;
}