Submission #724646

#	Time	Username	Problem	Language	Result	Execution time	Memory
724646		TimDee	Homecoming (BOI18_homecoming)	C++17	31 / 100	75 ms	100368 KiB

homecoming

//   you're already the best
//             _
//   ^ ^      //
// >(O_O)<___//
//   \ __ __  \
//    \\ \\ \\\\

#include "homecoming.h"
#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC optimize("O3","unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

using ll = long long;
#define int long long
//#define double long double
#define forn(i,n) for(int i=0; i<(n); ++i)
#define pb push_back
#define pi pair<int,int>
#define f first
#define s second 
#define vii(a,n) vector<int> a(n); forn(i,n) cin>>a[i];
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int inf = 1e18;
const int mod = 998244353;

struct sgt {
    vector<int> t,lazy;
    int sz;
    void push(int v) {
        t[v]+=lazy[v];
        lazy[2*v+1]+=lazy[v];
        lazy[2*v+2]+=lazy[v];
        lazy[v]=0;
    }
    sgt(int n) {
        sz=1; while (sz<n) sz<<=1;
        t.assign(2*sz-1,0);
        lazy.assign(4*sz-1,0);
    }
    int query(int v, int l, int r, int lx, int rx) {
        if (lazy[v]) push(v);
        if (rx<=l || r<=lx) return -inf;
        if (lx<=l && r<=rx) {
            return t[v];
        }
        int m=(l+r)>>1;
        int lq=query(2*v+1,l,m,lx,rx);
        int rq=query(2*v+2,m,r,lx,rx);
        t[v]=max(t[2*v+1],t[2*v+2]);
        return max(lq,rq);
    }
    int query(int l, int r) {
        return query(0,0,sz,l,r);
    }
    void add(int v, int l, int r, int lx, int rx, int x) {
        if (lazy[v]) push(v);
        if (rx<=l || r<=lx) return;
        if (lx<=l && r<=rx) {
            lazy[v]+=x;
            push(v);
            return;
        }
        int m=(l+r)>>1;
        add(2*v+1,l,m,lx,rx,x);
        add(2*v+2,m,r,lx,rx,x);
        t[v]=max(t[2*v+1],t[2*v+2]);
    }
    void add(int l, int r, int x) {
        add(0,0,sz,l,r,x);
    }
};

#undef int

long long solve(int N, int K, int *A, int *B) {
    #define int long long
    const int inf = 1e18;

    int ans=0;
    int n=N, k=K;
    vector<int> a,b;
    forn(i,n) a.pb(A[i]); forn(i,n) a.pb(a[i]);
    forn(i,n) b.pb(B[i]); forn(i,n) b.pb(b[i]); forn(i,n) b.pb(b[i]);
    vector<int> pra(2*n+1,0), prb(3*n+1,0);
    forn(i,2*n) pra[i+1]=pra[i]+a[i];
    forn(i,3*n) prb[i+1]=prb[i]+b[i];
    vector<int> dp(2*n+1,0);

    sgt st(2*n+1);
    if (n>5000) return 0;

    for (int i=1; i<=2*n; ++i) {
        dp[i]=max(dp[i],dp[i-1]);
        int sub=(i>=n)?dp[i-n]:0;
        int l=max(0ll,i-n);
        int r=i;
        int x=st.query(l,r);
        //cout<<l<<' '<<r<<' '<<x<<": "<<a[i-1]<<' '<<(prb[i+k-1]-prb[i-1])<<'\n';
        dp[i] = max(dp[i],x+a[i-1]-(prb[i+k-1]-prb[i-1])-sub);
        st.add(i,i+1,dp[i]);
        st.add(0,i,a[i-1]-b[i-1]);
        if (i+k-1>=n) st.add(0,i+k-n,b[i+k-1-n]);
        //for(auto&x:st.t) cout<<x<<' '; cout<<'\n';
        //for(auto&x:st.lazy) cout<<x<<' '; cout<<'\n';
        //forn(j,i+1) cout<<st.query(j,j+1)<<' '; cout<<'\n';
    }
    return dp[2*n];

    #undef int
}

Compilation message (stderr)

homecoming.cpp:5:1: warning: multi-line comment [-Wcomment]
    5 | //   \ __ __  \
      | ^
homecoming.cpp: In function 'long long int solve(int, int, int*, int*)':
homecoming.cpp:82:15: warning: unused variable 'inf' [-Wunused-variable]
   82 |     const int inf = 1e18;
      |               ^~~
homecoming.cpp:84:9: warning: unused variable 'ans' [-Wunused-variable]
   84 |     int ans=0;
      |         ^~~

• Subtask 1: 13 / 13
• Subtask 2: 18 / 18
• Subtask 3: 0 / 31
• Subtask 4: 0 / 38