Submission #1051559

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051559		pravcoder	Jobs (BOI24_jobs)	C++17	11 / 100	86 ms	33220 KiB

Main

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include <queue>
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> v2i;
typedef pair<int, int> pi;
typedef pair<ll, pi> pli;
typedef vector<ll> vl;
typedef vector<vl> v2l;
typedef vector<bool> vb;
typedef priority_queue<pli> pq;

#define pb push_back
#define mp make_pair
#define rep(i, n) for (int i = 0; i < n; i++)

//sub 1, 2, 3

vl p;
v2i adj;
vi par;
vl tp;
vb done;
vl req;
int nextjob;
int njd; // next job depth
ll m; // current money
bool sub3;

ll sub3solve() {
	v2i chains, req, tp;
	chains.resize(p.size());
	req.resize(p.size());
	tp.resize(p.size());
	pq nextjobs;
	// building chains
	for (auto start : adj[0]) {
		ll ctp = 0, creq = 0, pmr = 0, job = start;
		//cout << "\nCreating chain:";
		bool endchain = false;
		while (!endchain) {
			ctp += p[job];
			pmr += p[job];
			if (pmr < 0) {
				creq -= pmr;
				pmr = 0;
			}
			if (ctp > 0) {
				chains[start].pb(job);
				req[start].pb(0 - creq);
				tp[start].pb(ctp);
				ctp = 0; creq = 0; pmr = 0;
				if (chains[start].size() == 1) {
					nextjobs.push({ 0 - creq, {start, 0} });
				}
				//cout << " " << job;
			}
			if (adj[job].size() == 0) {
				endchain = true;
			}
			else {
				job = adj[job][0];
			}
		}
	}
	//cout << "\nChains built\n";
	//using the chains
	while (nextjobs.size() > 0 && 0 - nextjobs.top().first <= m) {
		//int req = nextjobs.top().first;
		int start = nextjobs.top().second.first;
		int index = nextjobs.top().second.second;
		nextjobs.pop();
		m += tp[start][index];
		if (index + 1 < tp[start].size()) {
			nextjobs.push({ req[start][index + 1], {start, index + 1} });
		}
	}
	return m;
}

ll dfs(int x) {
	// use dfs to find the maximum possible profit given that you do job x
	ll s = p[x];
	for (auto a : adj[x]) {
		s += max(0ll, dfs(a));
	}
	return s;
}

bool dfsu(int x, ll ctp=0, ll creq = 0, ll pmr=0, int depth=0) {
	// use dfs to update the current node, and returns if a new next job was found
	// tp: the total profit gained if this job is done
	// req: the total money requirement of going to this job
	// pmr: the total positive money reserve
	tp[x] = ctp;
	req[x] = creq;
	if (creq <= m && ctp > 0 && depth > njd) {
		nextjob = x;
		njd = depth;
		return true;
	}
	//cout << "Jobs upto job " << x << " can now be done with profit " << ctp << " and require " << creq << "\n";
	for (auto a : adj[x]) {
		if (!done[a]) {
			if (pmr + p[a] < 0) {
				if (dfsu(a, ctp + p[a], creq - (pmr + p[a]), 0, depth + 1)) {
					return true;
				}
			}
			else if (dfsu(a, ctp + p[a], creq, pmr + p[a], depth + 1)) {
				return true;
			}
		}
		else {
			if (dfsu(a)) {
				return true;
			}
		}
	}
	return false;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int n;
	ll s;
	cin >> n >> s;
	//if (s < 10e17) return 1;
	p.pb(s);
	par.pb(-1);
	sub3 = true;

	adj.resize(n + 1);
	done.resize(n + 1, false); done[0] = true;
	tp.resize(n + 1);
	req.resize(n + 1);
	par.resize(n + 1, 0);

	ll x, p_i;

	rep(i, n) {
		cin >> x >> p_i;
		adj[p_i].pb(i + 1);
		par[i + 1] = p_i;
		p.pb(x);
		if (p_i != i && p_i != 0) sub3 = false;
	}

	if (s == 1e18) {
		cout << dfs(0) - s;
		return 0;
	}

	if (sub3) {
		//cout << "Subtask 3 detected\n";
		m = s;
		cout << sub3solve() - s;
		return 0;
	}

	m = s;
	nextjob = -1;
	njd = 0;

	while (dfsu(0)) {
		int j = nextjob;
		//cout << "Jobs upto job " << j << " were done with profit " << tp[j] << "\n";
		while (!done[j]) {
			done[j] = true;
			m += p[j];
			j = par[j];
		}
		//cout << "Current money: " << m << "\n-------------------------------------------------------------\n";
		nextjob = -1;
		njd = 0;
	}

	cout << m - s;

	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'll sub3solve()':
Main.cpp:81:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   81 |   if (index + 1 < tp[start].size()) {
      |       ~~~~~~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 29
• Subtask 5: 0 / 31