Submission #798489

#	Time	Username	Problem	Language	Result	Execution time	Memory
798489		Sam_a17	Homecoming (BOI18_homecoming)	C++17	100 / 100	187 ms	180680 KiB

homecoming

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
// #include <atcoder/all>
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define blt(x) __builtin_popcount(x)
#define uniq(x) x.resize(unique(all(x)) - x.begin());
 
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
void print(long double t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T> void print(T v[],T n) {cerr << "["; for(int i = 0; i < n; i++) {cerr << v[i] << " ";} cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
// mt19937 myrand(131);
 
// for grid problems
int dx[8] = {1,0,-1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
char ch[4] = {'v', '>', '^', '<'};
 
long long ka() {
    long long x = 0;
    bool z = false;
    while (1)
    {
        char y = getchar();
        if (y == '-')
            z = true;
        else if ('0' <= y && y <= '9')
            x = x * 10 + y - '0';
        else
        {
            if (z)
                x *= -1;
            return x;
        }
    }
}
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if (str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  } else if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  }
}
 
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
const long long inf = -1e16;
 
 
long long solve(int N, int K, int *A, int *B) {
  vector<long long> a(2 * N), b(2 * N), pa(N), pb(N);
  int n = N, k = K;
 
  long long ans = 0;
  for(int i = 0; i < N; i++) {
    a[i] = A[i];
    b[i] = B[i];
    ans += a[i] - b[i];

    pa[i] = a[i];
    pb[i] = b[i];
    if(i) {
      pa[i] += pa[i - 1];
      pb[i] += pb[i - 1];
    }
  }
 
  ans = max(ans, 0ll);
 
  if(k == n) {
    return ans;
  }
 
  for(int t = 0; t <= 1; t++) {
    vector<long long> dp(n + 1), take(n + 1);
    if(t == 0) {
      take[0] = 0;
    } else {
      take[0] = a[0] - pb[k - 1];
    }
    dp[0] = take[0];

    if(t == 1) {
      for(int i = 1; i < n; i++) {
        if(i + k - 1 < n) {
          take[i] = max(take[i - 1] + a[i] - b[i + k - 1], dp[i - 1] + a[i] - (pb[i + k - 1] - pb[i - 1]));
        } else {
          take[i] = max(take[i - 1] + a[i], dp[i - 1] + a[i] - (pb[n - 1] - pb[i - 1]));
        }
        dp[i] = max(dp[i - 1], take[i]);
      }
    } else {
      for(int i = 1; i < n; i++) {
        if(i + k - 1 < n) {
          if(i == 1) {
            take[i] = dp[i - 1] + a[i] - (pb[i + k - 1] - pb[i - 1]);
          } else {
            take[i] = max(take[i - 1] + a[i] - b[i + k - 1], dp[i - 1] + a[i] - (pb[i + k - 1] - pb[i - 1]));
          }
        } else {
          if(i == 1) {
            take[i] = dp[i - 1] + a[i] - (pb[n - 1] - pb[i - 1] + pb[i + k - 1 - n]);
          } else {
            take[i] = max(take[i - 1] + a[i] - b[(i + k - 1) % n], dp[i - 1] + a[i] - (pb[n - 1] - pb[i - 1] + pb[i + k - 1 - n]));
          }
        }
        dp[i] = max(dp[i - 1], take[i]);
      }
    }

    for(int i = 0; i < n; i++) {
      ans = max(ans, dp[i]);
    }
  }
 
  return ans;
}

Compilation message (stderr)

homecoming.cpp: In function 'void setIO(std::string)':
homecoming.cpp:89:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
homecoming.cpp:90:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
homecoming.cpp:92:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
homecoming.cpp:93:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 18 / 18
• Subtask 3: 31 / 31
• Subtask 4: 38 / 38