Submission #162907

#	Time	Username	Problem	Language	Result	Execution time	Memory
162907		abacaba	Bigger segments (IZhO19_segments)	C++14	100 / 100	703 ms	60136 KiB

segments

#include <iostream>
#include <string>
#include <unordered_map>
#include <cstring>
#include <chrono>
#include <vector>
#include <map>
#include <random>
#include <set>
#include <algorithm>
#include <math.h>
#include <cstdio>
#include <stdio.h>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <deque>
#include <cassert>
#include <stack>
using namespace std;
 
#define pii pair<long long, long long>
#define mp make_pair
#define f first
#define se second
#define max3(a, b, c) max(a, max(b, c))
#define int long long
 
const int inf = 2e9;
 
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
 
struct node {
    node *l, *r;
    int key, pr;
    pii val, mx;
    node(int _key, pii _val) {
        pr = uniform_int_distribution<>(0, inf)(rng);
        l = r = NULL;
        key = _key, mx = val = _val;
    }
};
 
typedef node* pnode;
 
inline pii val(pnode t) {
    return t ? t->mx : mp(0LL, 0LL);
}
 
inline void upd(pnode &t) {
    if(t)
        t->mx = max3(t->val, val(t->l), val(t->r));
}
 
void split(pnode t, pnode &l, pnode &r, int key) {
    if(!t)
        return void(l = r = t);
    if(t->key <= key)
        split(t->r, t->r, r, key), l = t;
    else
        split(t->l, l, t->l, key), r = t;
    upd(l);
    upd(r);
}
 
void merge(pnode &t, pnode l, pnode r) {
    if(!l || !r)
        t = l ? l : r;
    else if(l->pr > r->pr)
        merge(l->r, l->r, r), t = l;
    else
        merge(r->l, l, r->l), t = r;
    upd(t);
}
 
pnode root = NULL;
 
const int mod = 1e9 + 7;
const int N = 5e5 + 15;
int n, a[N], p[N];
pii dp[N];

inline void insert(pnode &t, pnode nw) {
    pnode t1, t2, t3, t4;
    split(root, t1, t2, nw->key - 1);
    split(t2, t3, t4, nw->key);
    if(t3)
        t3->val = max(t3->val, nw->val);
    else
        t3 = nw;
    merge(t2, t3, t4);
    merge(root, t1, t2);
}

main() {
    ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> a[i];
        p[i] = p[i-1] + a[i];
    }
    root = new node(0, mp(1, 0));
    for(int i = 1; i <= n; ++i) {
        pnode t1, t2;
        split(root, t1, t2, p[i]);
        dp[i] = val(t1);
        merge(root, t1, t2);
        insert(root, new node(2 * p[i] - p[dp[i].se], mp(dp[i].f + 1, i)));
    }
    cout << dp[n].f << endl;
    return 0;
}

Compilation message (stderr)

segments.cpp:95:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27