ZOJ 3204 Connect them MST-Kruscal

这道题目麻烦在输出的时候需要按照字典序输出，不过写了 Compare 函数还是比较简单的

因为是裸的 Kruscal ，所以就直接上代码了～

Source Code :

//#pragma comment(linker, "/STACK:16777216") //for c++ Compiler
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cmath>
#include <stack>
#include <string>
#include <map>
#include <set>
#include <list>
#include <queue>
#include <vector>
#include <algorithm>
#define Max(a,b) (((a) > (b)) ? (a) : (b))
#define Min(a,b) (((a) < (b)) ? (a) : (b))
#define Abs(x) (((x) > 0) ? (x) : (-(x)))
#define MOD 1000000007
#define pi acos(-1.0)

using namespace std;

typedef long long           ll      ;
typedef unsigned long long  ull     ;
typedef unsigned int        uint    ;
typedef unsigned char       uchar   ;

template<class T> inline void checkmin(T &a,T b){if(a>b) a=b;}
template<class T> inline void checkmax(T &a,T b){if(a<b) a=b;}

const double eps = 1e-8         ;
const int N = 210               ;
const int M = 1100011*2         ;
const ll P = 10000000097ll      ;
const double MINN = -999999999.9;
const int INF = 0x3f3f3f3f      ;
const int MAXN = 110            ;

int root[MAXN];
struct Edge {
    int from,to;
    int w;
} edge[MAXN * MAXN];

int tol;
Edge ans[MAXN * MAXN];
int cnt;

void addedge (int u, int v, int w) {
    edge[tol].from = u;
    edge[tol].to = v;
    edge[tol].w = w;
    ++tol;
}

bool cmp1 (Edge a, Edge b) {
    if(a.w != b.w)    return a.w < b.w;
    else if (a.from != b.from)  return a.from < b.from;
    else return a.to < b.to;
}

bool cmp2 (Edge a, Edge b) {
    if (a.from != b.from)   return a.from < b.from;
    else return a.to < b.to;
}

int find (int x) {
    if (root[x] == -1)  return x;
    return root[x] = find (root[x]);
}

void kruscal () {
    memset (root,-1,sizeof(root));
    cnt = 0;    //加入最小生成树的边
    for (int k = 0; k < tol; ++k) {
        int u = edge[k].from;
        int v = edge[k].to;
        int t1 = find(u);
        int t2 = find(v);
        if(t1 != t2) {
            ans[cnt++] = edge[k];
            root[t1] = t2;
        }
    }
}

int main () {
    int T;
    scanf("%d",&T);
    int n;
    while (T--) {
        scanf ("%d",&n);
        tol = 0;
        int w;
        for (int i = 1; i <= n; ++i) {
          for (int j = 1; j <= n; ++j) {
              scanf("%d",&w);
              if(j <= i || w == 0)    continue;
              addedge(i, j, w);
          }
        }
        sort (edge, edge + tol, cmp1);
        kruscal ();
        if (cnt != n - 1) {
            printf("-1\n");
            continue;
        } else {
            sort (ans, ans + cnt, cmp2);
            for (int i = 0; i < cnt - 1; ++i) {
              printf("%d %d ", ans[i].from, ans[i].to);
            }
            printf("%d %d\n", ans[cnt - 1].from, ans[cnt - 1].to);
        }
    }
    return 0;
}