oj.uz

Submission #885668

# Submission time Handle Problem Language Result Execution time Memory
885668 2023-12-10T11:57:23 Z Tob Islands (IOI08_islands) C++14
34 / 100
 154 ms 63712 KB 
#include <bits/stdc++.h>

#define ll long long
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define pb push_back
#define FIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

using namespace std;

typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

const ll N = 1e6 + 7, inf = 1e18;

ll n, ro, sp, res;
int a[N], b[N], bio[N], cyc[N], deg[N];
ll dp[N], dis[N], rdis[N], pr[N], pr2[N], suf[N], suf2[N];
pll cur[N];
queue <int> q;

void Merge(pll& x, ll y) {
	if (y >= x.F) x = {y, x.F};
	else x = {x.F, max(x.S, y)};
}

void dfs() {
	int x = q.front();
	q.pop();
	pii y = {a[x], b[x]};
	res = max(res, cur[x].F + cur[x].S);
	dp[x] = cur[x].F;
	Merge(cur[y.F], dp[x] + y.S);
	if (cyc[y.F]) return;
	deg[y.F]--;
	if (!deg[y.F]) q.push(y.F);
}

int main () {
	FIO;
	cin >> n;
	
	for (int i = 1; i <= n; i++) {
		cin >> a[i] >> b[i];
		deg[a[i]]++;
	}
	
	for (int i = 1; i <= n; i++) {
		if (bio[i]) continue;
		int x = a[i], y = i;
		bio[i] = i;
		while (!bio[x]) {
			bio[x] = i;
			y = x;
			x = a[x];
		}
		if (bio[x] == i) {
			cyc[y] = 1;
			while (x != y) {
				cyc[x] = 1;
				x = a[x];
			}
		}
	}
	memset(bio, 0, sizeof bio);
	for (int i = 1; i <= n; i++) if (!deg[i]) q.push(i);
	while (!q.empty()) dfs();
	
	ll sum = 0;
	for (int i = 1; i <= n; i++) {
		if (bio[i]) continue;
		int x = a[i], y = i;
		bio[i] = i;
		while (!bio[x]) {
			bio[x] = i;
			y = x;
			x = a[x];
		}
		if (bio[x] == i) {
			res = 0;
			vector <int> v; v = {0, y};
			while (x != y) {
				v.pb(x);
				x = a[x];
			}
			int siz = v.size();
			pr[0] = pr2[0] = suf[siz] = suf2[siz] = -inf;
			
			for (int i = siz-1; i; i--) rdis[i] = rdis[i+1] + (i < siz-1)*b[v[i]];
			for (int i = 1; i < siz; i++) {
				dis[i] = dis[i-1] + b[v[i-1]];
				dp[v[i]] = cur[v[i]].F;
				pr[i] = max(pr[i-1], dp[v[i]] + dis[i]);
				pr2[i] = max(pr2[i-1], dp[v[i]] + rdis[i]);
			}
			
			for (int i = siz-1; i; i--) {
				suf[i] = max(suf[i+1], dp[v[i]] + dis[i]);
				suf2[i] = max(suf2[i+1], dp[v[i]] + rdis[i]);			
			}
			for (int i = 1; i < siz; i++) {
//				cout << i << "i " << v[i] << "x " << dis[i] << "d " << rdis[i] << "rd " << pr[i] << "p " << pr2[i] << "pp " << suf[i] << "s " << suf2[i] << "ss " << dp[v[i]] << "dp\n";
				res = max(res, dp[v[i]] + max(suf[i+1] - dis[i], pr[i-1] + rdis[i] + b[v.back()]));
				res = max(res, dp[v[i]] + max(pr2[i-1] - rdis[i], suf2[i+1] + dis[i] + b[v.back()]));
			}
			sum += res;
		}
	}
	
	cout << sum;

	return 0;
}

Subtask #1
21.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 20828 KB Output is correct
2 Incorrect 3 ms 20828 KB Output isn't correct
3 Correct 3 ms 20828 KB Output is correct
4 Correct 3 ms 20828 KB Output is correct
5 Correct 3 ms 20828 KB Output is correct
6 Correct 3 ms 20828 KB Output is correct
7 Incorrect 3 ms 20828 KB Output isn't correct
8 Incorrect 3 ms 20828 KB Output isn't correct
9 Correct 3 ms 20828 KB Output is correct
10 Incorrect 3 ms 20852 KB Output isn't correct
11 Correct 3 ms 20828 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 21080 KB Output is correct
2 Correct 3 ms 20856 KB Output is correct

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 3 ms 20896 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 6 ms 21084 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 26336 KB Output is correct
2 Incorrect 18 ms 28632 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 33 ms 32824 KB Output is correct
2 Correct 33 ms 33832 KB Output is correct
3 Correct 45 ms 41564 KB Output is correct

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 61 ms 36692 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 141 ms 37200 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 150 ms 63648 KB Output is correct
2 Incorrect 154 ms 63712 KB Output isn't correct
3 Halted 0 ms 0 KB -