Submission #949689

#TimeUsernameProblemLanguageResultExecution timeMemory
949689VinhLuuSplit the sequence (APIO14_sequence)C++17
89 / 100
1463 ms90196 KiB
#include <bits/stdc++.h>
//#define int long long
#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(lmao) lmao.begin(), lmao.end()

using namespace std;

typedef pair<int,int> pii;
typedef tuple<int,int,int> tp;
const int N = 2e5 + 5;
const ll oo = -1e12;
const int K = 205;
const int mod = 998244353;
//const int base = 23;

ll n, k, a[N], dp[N][5], s[N], pre, nx;

int f[N][K];

ll cal(int i,int j){
    return 1ll * (s[j] - s[i]) * (s[n] - s[j]);
}

void solve(int j,int l,int r,int pl,int pr){
    if(l > r) return;
    int mid = (l + r) / 2;
    dp[mid][nx] = oo;
    for(int i = pl; i <= min(mid - 1, pr); i ++){
        ll val = dp[i][pre] + cal(i, mid);
        if(val > dp[mid][nx]){
            dp[mid][nx] = val;
            f[mid][j] = i;
        }
    }
    solve(j, l, mid - 1, pl, f[mid][j]);
    solve(j, mid + 1, r, f[mid][j], pr);
}

signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    #define task "v"
    if(fopen(task ".inp","r")){
        freopen(task ".inp","r",stdin);
        freopen(task ".out","w",stdout);
    }

    cin >> n >> k;
    if(n > 1e5) return 0;
    for(int i = 1; i <= n; i ++){
        cin >> a[i];
        s[i] = s[i - 1] + a[i];
    }
    if(k == 0){
        cout << 0;
        return 0;
    }
    for(int j = 0; j <= 1; j ++){
        for(int i = 0; i <= n; i ++){
            dp[i][j] = oo;
        }
    }

    pre = 0, nx = 1;
    for(int i = 1; i <= n; i ++) dp[i][0] = 1ll * s[i] * (s[n] - s[i]), f[i][0] = 0;
    for(int j = 2; j <= k; j ++){
        solve(j, j, n, 1, n);
        swap(pre, nx);
    }
    ll ans = oo;
    int tmp = 0, cnt = k;
    for(int i = 1; i <= n; i ++){
        if(ans < dp[i][pre]){
            ans = dp[i][pre];
            tmp = i;
        }
    }
    cout << ans << "\n";

    vector<int> vr;
    vr.pb(tmp);
    while(f[tmp][cnt]){
        vr.pb(f[tmp][cnt]);
        tmp = f[tmp][cnt];
        cnt--;
    }
    for(int i = vr.size() - 1; i >= 0; i --) cout << vr[i] << " ";

}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen(task ".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen(task ".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
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