POJ 2492 解题报告

/*
ID: thestor1
LANG: C++
TASK: poj2492
*/
#include <iostream>
#include <fstream>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <limits>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <cassert>

using namespace std;

const int MAXN = 2000;

void makeset(vector<int> &parent, vector<int> &rank, const int N)
{
for (int u = 0; u < N; ++u)
{
parent[u] = u;
rank[u] = 0;
}
}

int find(int u, vector<int> &parent)
{
if (parent[u] != u)
{
parent[u] = find(parent[u], parent);
}
return parent[u];
}

void union_set(int u, int v, vector<int> &parent, vector<int> &rank)
{
int ru = find(u, parent);
int rv = find(v, parent);
if (ru == rv)
{
return;
}

if (rank[ru] < rank[rv])
{
parent[ru] = rv;
}
else if (rank[rv] < rank[ru])
{
parent[rv] = ru;
}
else
{
parent[ru] = rv;
rank[rv]++;
}
}

int main()
{
vector<int> parent(2 * MAXN);
vector<int> rank(2 * MAXN);

int T;
scanf("%d", &T);
for (int t = 0; t < T; ++t)
{
int N, M;
scanf("%d%d", &N, &M);
makeset(parent, rank, N << 1);

bool suspicious = false;
for (int i = 0; i < M; ++i)
{
int u, v;
scanf("%d%d", &u, &v);
u--, v--;

// already have a conclusion, no need to process
if (suspicious)
{
continue;
}

if (find(u, parent) == find(v, parent) || find(u + N, parent) == find(v + N, parent))
{
suspicious = true;
}
else
{
union_set(u, v + N, parent, rank);
union_set(v, u + N, parent, rank);
}
}

printf("Scenario #%d:\n", t + 1);
if (suspicious)
{
printf("Suspicious bugs found!\n\n");
}
else
{
printf("No suspicious bugs found!\n\n");
}
}
return 0;
}