Submission #256815

#	Time	Username	Problem	Language	Result	Execution time	Memory
256815		Bruteforceman	Arcade (NOI20_arcade)	C++11	85 / 100	1100 ms	44580 KiB

Arcade

#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 10;
int dp[maxn];
int a[maxn], t[maxn];
map <int, int> cmp;
int bit[maxn];
int n, m;

struct node {
  int idx;
  int x, y;
  node (int idx, int x, int y) : idx(idx), x(x), y(y) {}
  node () {}
  bool operator < (node p) const {
    return x < p.x;
  }
};
vector <node> v[maxn];

void update(int x, int val) {
  for(int i = x; i <= m; i += i & (-i)) {
    bit[i] = max(bit[i], val);  
  }
}
void remove(int x) {
  for(int i = x; i <= m; i += i & (-i)) {
    bit[i] = 0;
  }
}
int query(int x) {
  int ans = 0;
  for(int i = x; i > 0; i -= i & (-i)) {
    ans = max(ans, bit[i]);
  }
  return ans;
}

void solve(int l, int r) {
  if(l == r) {
    for(auto i : v[l]) dp[i.idx] = max(dp[i.idx], 1);
    return ;
  }
  int mid = (l + r) >> 1;
  solve(l, mid);
  vector <node> left, right;
  for(int i = l; i <= mid; i++) {
    for(auto j : v[i]) left.push_back(j);
  }
  for(int i = mid + 1; i <= r; i++) {
    for(auto j : v[i]) right.push_back(j);
  }
  sort(left.begin(), left.end());
  sort(right.begin(), right.end());
  int pt = 0;
  for(auto i : right) {
    while(pt < left.size() && left[pt].x < i.x) {
      update(left[pt].y, dp[left[pt].idx]);
      ++pt;
    }
    dp[i.idx] = max(dp[i.idx], 1 + query(i.y - 1));
  }
  for(auto i : left) remove(i.y);
  solve(mid + 1, r);
}
int main() {
  scanf("%d %d", &n, &m);
  for(int i = 0; i < m; i++) {
    scanf("%d", &t[i]);
  }
  map <int, int> cmp, cmpY;
  for(int i = 0; i < m; i++) {
    scanf("%d", &a[i]);
    cmp[a[i]];
    cmpY[a[i] - t[i]];
  }
  int idx = 0;
  for(auto &i : cmp) {
    i.second = ++idx;
  }
  int idY = 0;
  for(auto &i : cmpY) {
    i.second = ++idY;
  }
  for(int i = 0; i < m; i++) {
    v[cmp[a[i]]].emplace_back(i, a[i] + t[i], cmpY[a[i] - t[i]]);
  }
  solve(1, m);
  printf("%d\n", *max_element(dp, dp + m));
  return 0;
}

Compilation message (stderr)

Arcade.cpp: In function 'void solve(int, int)':
Arcade.cpp:57:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(pt < left.size() && left[pt].x < i.x) {
           ~~~^~~~~~~~~~~~~
Arcade.cpp: In function 'int main()':
Arcade.cpp:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &n, &m);
   ~~~~~^~~~~~~~~~~~~~~~~
Arcade.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &t[i]);
     ~~~~~^~~~~~~~~~~~~
Arcade.cpp:73:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &a[i]);
     ~~~~~^~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 14 / 14
• Subtask 6: 20 / 20
• Subtask 7: 0 / 15