Submission #918232

#	Time	Username	Problem	Language	Result	Execution time	Memory
918232		wii	Split the sequence (APIO14_sequence)	C++17	71 / 100	276 ms	131072 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
 
typedef double db;
typedef long long ll;
typedef long double ld;
 
#define int ll
typedef pair<int, int> pii;
 
#define lx (id << 1)
#define rx (lx  1)
#define gcd __gcd
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define bit(i, mask) ((mask) >> (i) & 1)
#define reset(x, val) memset(x, val, sizeof(x))
#define foru(i,a,b) for(int i = (a); i <= (b); ++i)
#define ford(i,a,b) for(int i = (a); i >= (b); --i)
#define FastIO ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
 
template<typename T> bool maximize(T &res, const T &val) { if (res < val) { res = val; return true; } return false; }
template<typename T> bool minimize(T &res, const T &val) { if (val < res) { res = val; return true; } return false; }
 
const ll Linf = 0x3f3f3f3f3f3f3f3f;
const int Inf = 0x3f3f3f3f;
const ll Mod = 1e9 + 7;
const ll Mod2 = ll(1e9) + 9;
const int Lim = 1e6 + 5;
const int inv6 = 166666668;
 
// #define Sieve
#ifdef Sieve
    vector<int> pr;
    vector<int> lpf;
    void Linear_sieve(int n = Lim) {
        pr.assign(1, 2);
        lpf.assign(n + 1, 2);
 
        for (int x = 3; x <= n; x += 2) {
            if (lpf[x] == 2) pr.push_back(lpf[x] = x);
            for (int i = 1; i < pr.size() && pr[i] <= lpf[x] && pr[i] * x <= n; ++i)
                lpf[pr[i] * x] = pr[i];
        }
    }
#endif
 
/// ====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====*====
 
const int base = 3;
const int N = 1e5 + 5;
const int K = 200 + 1;
const int dx[] = {+1, -1, 0, 0};
const int dy[] = {0, 0, +1, -1};
const int block_size = sqrt(2e9) + 2;
 
struct Line {
    mutable int a, b;
    Line() = default;
    Line(int a, int b):
        a(a), b(b) {}
 
    bool operator< (const Line &x) const { return a < x.a; };
    int operator() (int x) const { return a * x + b; }
};
 
struct LineContainer {
    vector<Line> st;
 
    int div(int a, int b) {
        return a / b - ((a ^ b) < 0 && a % b);
    }
 
    ld isect(const Line &x, const Line &y) {
        return ld(y.b - x.b) / (x.a - y.a);
    }

    int bad(const Line &a, const Line &b, const Line &c) {
        if (b.a == c.a) return true;
        return isect(a, b) < isect(b, c);
    }
 
    void add(int k, int m) {
        int top = st.size();
        Line l = Line(k, m);

        while (top >= 2 && bad(st[top - 2], st[top - 1], l))
            st.pop_back(), --top;
 
        st.push_back(l);
    }
 
    int query(int x) {
        int l = 0, r = st.size() - 1;
        while (l < r) {
            int mid = (l + r) >> 1;
            if (isect(st[mid], st[mid + 1]) > x)
                l = mid + 1;
            else
                r = mid;
        }
 
        return st[l](x);
    }
};
 
int n, k;
int a[N], pref[N];
int dp[N][K];
 
LineContainer cht;
int f(int l, int r) {
    return pref[r] - pref[l - 1];
}
 
/**
7 3
4 1 3 4 0 2 3
**/
 
void solve() {
    cin >> n >> k;
    foru(i, 1, n) cin >> a[i];
    foru(i, 1, n) pref[i] = pref[i - 1] + a[i];
 
    foru(i, 0, n) foru(z, 0, k) dp[i][z] = -Linf;
 
    dp[0][0] = 0;
	foru(z, 1, k) {
		cht.st.clear();
		foru(i, 1, n - 1) {
			int j = i - 1;
			cht.add(-pref[j], dp[j][z - 1]);

			dp[i][z] = cht.query(f(i + 1, n)) + f(i + 1, n) * pref[i];
		}
	}
 
    int ans = -Linf;
    foru(i, 1, n - 1) maximize(ans, dp[i][k]);
 
    cout << ans << "\n";
    for (int cur = n - 1, z = k; cur > 0 && z > 0; --cur) {
        if (dp[cur][z] == ans) {
            for (int j = 0; j < cur; ++j)
                if (dp[j][z - 1] + f(j + 1, cur) * f(cur + 1, n) == ans) {
                    cout << cur << " ";
 
                    cur = j + 1;
                    --z;
                    ans = dp[j][z];
                    break;
                }
        }
    }
}
 
signed main() {
    FastIO;
 
    #define task ""
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
 
    #define task "Test"
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    } else if (0) {
        ofstream fout(task".inp");
        fout.close();
 
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
 
    #ifdef Sieve
        Linear_sieve();
    #endif
 
    int ntest = 1;
    // cin >> ntest;
    while (ntest--) {
        //cout << "Case " << q << ": " << "\n";
        solve();
        cout << "\n";
    }
 
    return 0;
}
 
/**  /\_/\
 *  (= ._.)
 *  / >TL \>AC
**/

Compilation message (stderr)

sequence.cpp:167: warning: "task" redefined
  167 |     #define task "Test"
      | 
sequence.cpp:161: note: this is the location of the previous definition
  161 |     #define task ""
      | 
sequence.cpp: In function 'int main()':
sequence.cpp:163:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:164:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  164 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:169:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  169 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:170:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  170 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:175:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  175 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:176:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  176 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29