Submission #97523

#	Time	Username	Problem	Language	Result	Execution time	Memory
97523		tincamatei	Dreaming (IOI13_dreaming)	C++14	100 / 100	122 ms	14948 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 100000;
vector<pair<int, int> > graph[MAX_N];

int dist[MAX_N], papa[MAX_N], distpapa[MAX_N];
int diam[MAX_N], comp[MAX_N], top;
bool viz[MAX_N];

int calcDist(int nod, int p) {
	int rez = nod;
	viz[nod] = true;
	for(auto it: graph[nod]) {
		if(it.first != p) {
			dist[it.first] = dist[nod] + it.second;
			papa[it.first] = nod;
			distpapa[it.first] = it.second;
			int x = calcDist(it.first, nod);
			if(dist[x] >= dist[rez])
				rez = x;
		}
	}
	return rez;
}

int getFarthest(int nod) {
	int x;
	
	dist[nod] = 0;
	papa[nod] = -1;
	nod = calcDist(nod, -1);
	
	x = nod;
	int d = dist[nod];
	top = 0;

	while(nod != -1) {
		diam[top++] = d;
		d -= distpapa[nod];
		nod = papa[nod];
	}

	return x;
}

bool cmp(int a, int b) {
	return a > b;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	int tc = 0;
	for(int i = 0; i < M; ++i) {
		graph[A[i]].push_back(make_pair(B[i], T[i]));
		graph[B[i]].push_back(make_pair(A[i], T[i]));
	}
	
	int bd = 0;

	for(int i = 0; i < N; ++i) {
		if(!viz[i]) {
			int c1, c2;
			c1 = getFarthest(i);
			c2 = getFarthest(c1);
			
			comp[tc] = 2000000000;

			int d = diam[0];
			bd = max(bd, d);
			for(int i = 0; i < top; ++i)
				comp[tc] = min(comp[tc], max(diam[i], d - diam[i]));
			tc++;
		}
	}
	
	sort(comp, comp + tc, cmp);
	if(tc == 1)
		return bd;
	else if(tc == 2)
		return max(bd, comp[0] + comp[1] + L);
	else {
		int rez = 2000000000;
		for(int i = 0; i < 3; ++i) {
			int xd[3], t = 1;
			xd[0] = comp[i];
			for(int j = 0; j < 3; ++j)
				if(i != j)
					xd[t++] = comp[j] + L;
			sort(xd, xd + t, cmp);
			rez = min(rez, xd[0] + xd[1]);
		}
		return max(bd, rez);
	}
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:64:12: warning: variable 'c2' set but not used [-Wunused-but-set-variable]
    int c1, c2;
            ^~

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23