洛谷__P1525 [NOIP 2010 提高组] 关押罪犯（拓展并查集）

题目链接：P1525 [NOIP 2010 提高组] 关押罪犯 - 洛谷

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题目大意：

将罪犯分到两个监狱，使得同一监狱内罪犯之间的最大怨气值最小，

输出这个最小值。若无冲突输出0。

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代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<unordered_set>
#include<unordered_map>
#include<bitset>
#include<tuple>
#define inf 72340172838076673
#define int long long
#define endl '\n'
#define F first
#define S second
#define  mst(a,x) memset(a,x,sizeof (a))
using namespace std;
typedef pair<int, int> pii;

const int N = 200086, mod = 998244353;

int n, m;
int f[N];
struct node {
    int a, b, c;
    bool operator<(const node &b) {
        return c > b.c;
    }
} e[N];

int find(int u) {
    if (f[u] == u) return u;
    return f[u] = find(f[u]);
}

void merge(int a, int b) {
    a = find(a), b = find(b);
    if (a != b) f[a] = b;
}

void solve() {

    cin >> n >> m;
    for (int i = 1; i <= 2 * n; i++) f[i] = i;
    for (int i = 1; i <= m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        e[i] = {a, b, c};
    }
    
    sort(e + 1, e + m + 1);
    
    for (int i = 1; i <= m; i++) {
        auto [a, b, c] = e[i];
        merge(a, b + n);
        merge(a + n, b);
        if (find(a) == find(a + n) || find(b) == find(b + n)) {
            cout << c << endl;
            return ;
        }
    }
    cout << 0 << endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    
    int T = 1;
// cin >> T;
    while (T--) solve();
    
    return 0;
}