oj.uz

Submission #76721

# Submission time Handle Problem Language Result Execution time Memory
76721 2018-09-16T12:20:20 Z Mamnoon_Siam Highway Tolls (IOI18_highway) C++17
51 / 100
 404 ms 36368 KB 
#include "highway.h"
#include <bits/stdc++.h>
using namespace std;

#define debug(s) cout << #s << " = " << s << endl

typedef long long ll;
typedef pair<int, int> ii;

const int maxn = 500005;

namespace {

vector<int> L, R, g[maxn], t[maxn], vis, lvl, pe, wot, where;
ll pathLen, A, B;
int S, T, tym = 0, n, m;

}

void bfs(int root) {
	queue<int> Q;
	Q.emplace(root);
	lvl[root] = 0;
	pe[root] = -1, vis[root] = 1;

	while(Q.size()) {
		int u = Q.front();
		Q.pop();
		for(int i : g[u]) {
			int v = L[i] ^ R[i] ^ u;
			if(!vis[v]) {
				vis[v] = 1;
				Q.emplace(v);
				lvl[v] = lvl[u] + 1;
				pe[v] = i;

				t[u].emplace_back(i);
				t[v].emplace_back(i);
			}
		}
	}
}

void dfs(int u) {
	vis[u] = 1;
	wot[tym] = u;
	where[u] = tym++;
	for(int i : t[u]) {
		int v = L[i] ^ R[i] ^ u;
		if(!vis[v]) {
			dfs(v);
		}
	}
}

void find_pair(int _N, std::vector<int> _U, std::vector<int> _V, int _A, int _B) {
	n = _N, L = _U, R = _V, A = _A, B = _B, m = _U.size();
	vis.assign(n, 0), lvl.assign(n, 0), pe.assign(n, 0), wot.assign(n, 0), where.assign(n, 0);

	for(int i = 0; i < m; i++) {
		g[L[i]].emplace_back(i);
		g[R[i]].emplace_back(i);
		// cout << i << " ----> " << L[i] << ' ' << R[i] << endl;
	}

	{
		vector<int> w(m);
		pathLen = ask(w) / A;
		// debug(pathLen);
	}

	int root;
	{
		int lo = 0, hi = m - 1, mid, ret = -1;
		while(lo <= hi) {
			mid = lo + hi >> 1;
			vector<int> w(m);
			for(int i = 0; i <= mid; i++) {
				w[i] = 1;
			}
			if(ask(w) != A * pathLen) {
				ret = mid;
				hi = mid - 1;
			} else {
				lo = mid + 1;
			}
		}
		root = ret == -1 ? -1 : L[ret];
	}

	// debug(root);

	bfs(root);
	fill(vis.begin(), vis.end(), 0);
	dfs(root);
	// for(int b : wot) cout << b << ' '; cout << endl;
	// for(int b : pe) cout << b << ' '; cout << endl;

	S = T = -1;

	{
		int lo = 0, hi = n - 1, mid;
		while(lo <= hi) {
			mid = lo + hi >> 1;
			vector<int> w(m, 1);
			for(int i = 0; i <= mid; i++) {
				w[pe[wot[i]]] = 0;
			}
			if(ask(w) == A * pathLen) {
				S = wot[mid];
				hi = mid - 1;
			} else {
				lo = mid + 1;
			}
		}
	}

	{
		int lo = 0, hi = n - 1, mid;
		while(lo <= hi) {
			mid = lo + hi >> 1;
			vector<int> w(m, 1);
			for(int i = 0; i <= mid; i++) {
				w[pe[wot[i]]] = 0;
			}
			int u = S;
			while(pe[u] != -1) {
				w[pe[u]] = 1;
				u = u ^ L[pe[u]] ^ R[pe[u]];
			}
			// for(int i = 0; i < m; i++) cout << i << ' '; cout << endl;
			// for(int b : w) cout << b << ' '; cout << endl;

			// debug(ask(w));

			if(ask(w) == A * (pathLen - lvl[S]) + B * lvl[S]) {
				T = wot[mid];
				hi = mid - 1;
			} else {
				lo = mid + 1;
			}
		}
	}
	// debug(S), debug(T);
	answer(S, T);
}

Compilation message

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:76:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    mid = lo + hi >> 1;
          ~~~^~~~
highway.cpp:104:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    mid = lo + hi >> 1;
          ~~~^~~~
highway.cpp:121:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
    mid = lo + hi >> 1;
          ~~~^~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23800 KB Output is correct
2 Correct 24 ms 23800 KB Output is correct
3 Correct 24 ms 23800 KB Output is correct
4 Correct 23 ms 23808 KB Output is correct
5 Correct 24 ms 23800 KB Output is correct
6 Correct 25 ms 23784 KB Output is correct
7 Correct 23 ms 23804 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 24 ms 23800 KB Output is correct
10 Correct 24 ms 23808 KB Output is correct
11 Correct 24 ms 23816 KB Output is correct
12 Correct 24 ms 23808 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 23928 KB Output is correct
2 Correct 46 ms 24924 KB Output is correct
3 Correct 315 ms 33988 KB Output is correct
4 Correct 326 ms 33988 KB Output is correct
5 Correct 323 ms 34036 KB Output is correct
6 Correct 301 ms 34000 KB Output is correct
7 Correct 338 ms 34004 KB Output is correct
8 Correct 298 ms 33912 KB Output is correct
9 Correct 304 ms 34004 KB Output is correct
10 Correct 343 ms 33896 KB Output is correct
11 Correct 317 ms 34252 KB Output is correct
12 Correct 315 ms 34600 KB Output is correct
13 Correct 319 ms 34408 KB Output is correct
14 Correct 293 ms 34448 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 25208 KB Output is correct
2 Correct 62 ms 26580 KB Output is correct
3 Correct 89 ms 27924 KB Output is correct
4 Correct 192 ms 35512 KB Output is correct
5 Correct 220 ms 35464 KB Output is correct
6 Correct 238 ms 35956 KB Output is correct
7 Correct 215 ms 36368 KB Output is correct
8 Correct 204 ms 35692 KB Output is correct
9 Correct 194 ms 35792 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23884 KB Output is correct
2 Correct 47 ms 24952 KB Output is correct
3 Correct 245 ms 31696 KB Output is correct
4 Correct 336 ms 33888 KB Output is correct
5 Correct 251 ms 33912 KB Output is correct
6 Correct 292 ms 33996 KB Output is correct
7 Correct 260 ms 33912 KB Output is correct
8 Correct 280 ms 33896 KB Output is correct
9 Correct 297 ms 33896 KB Output is correct
10 Correct 283 ms 33896 KB Output is correct
11 Correct 328 ms 34280 KB Output is correct
12 Correct 348 ms 34620 KB Output is correct
13 Correct 336 ms 34476 KB Output is correct
14 Correct 344 ms 34432 KB Output is correct
15 Correct 310 ms 34000 KB Output is correct
16 Correct 274 ms 33904 KB Output is correct
17 Correct 331 ms 34388 KB Output is correct
18 Correct 306 ms 34604 KB Output is correct
19 Correct 268 ms 34004 KB Output is correct
20 Correct 333 ms 34804 KB Output is correct
21 Correct 255 ms 34764 KB Output is correct
22 Correct 265 ms 34776 KB Output is correct
23 Correct 250 ms 34704 KB Output is correct
24 Correct 316 ms 34756 KB Output is correct
25 Correct 404 ms 36212 KB Output is correct

Subtask #5
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 24956 KB Output is correct
2 Correct 54 ms 24984 KB Output is correct
3 Correct 361 ms 34216 KB Output is correct
4 Incorrect 370 ms 34548 KB Output is incorrect: {s, t} is wrong.
5 Halted 0 ms 0 KB -

Subtask #6
0 / 31.0

# Verdict Execution time Memory Grader output
1 Incorrect 53 ms 24876 KB Output is incorrect: {s, t} is wrong.
2 Halted 0 ms 0 KB -