繁忙的都市

川长思鸟来 2021-11-13 15:10 190阅读 0赞

[题面][Link 1]

主要思路就是将所有的边储存起来，然后进行贪心地选择，期间需要判断两个端点是否有关联，这一过程通过并查集实现。

1 #include <iostream> 
     2 #include <cstdio>
     3 #include <algorithm>
     4 #include <cmath>
     5 using namespace std;
     6 
     7 const int maxn = 500;
     8 
     9 int n, m;
    10 int x[maxn], y[maxn], f[maxn];
    11 int ans = 0;
    12 
    13 struct node {
    14     int x, y;
    15     int val;
    16 }dis[50100];
    17 
    18 bool cmp(node a, node b) {
    19     return a.val < b.val;
    20 }
    21 
    22 int find(int x) {
    23     int r = x;
    24     while(r != f[r]) r = f[r];
    25     int i = x, j;
    26     while(f[i] != r) {  
    27         j = f[i];  
    28         f[i] = r;  
    29         i = j;  
    30     }
    31     return r;  
    32 }
    33 
    34 void merge(int x, int y) {
    35     x = find(x);
    36     y = find(y);
    37     if(x != y) f[y] = x;
    38 }
    39 
    40 int main() {
    41     cin >> n >> m;
    42     for(int i = 1; i <= m; i++) {
    43         cin >> dis[i].x >> dis[i].y >> dis[i].val;
    44     }
    45     for(int i = 1; i <= n; i++) f[i] = i;
    46 
    47     sort(dis + 1, dis + m + 1, cmp);
    48     int tmp = 0, maxn = 0;
    49     for(int i = 1; i <= m; i++) {
    50         if(find(dis[i].x) != find(dis[i].y)) {
    51             merge(dis[i].x, dis[i].y);
    52             tmp++;
    53             maxn = max(maxn, dis[i].val);
    54         }
    55         if(tmp == n - 1) break;
    56     }
    57 
    58     cout << tmp << ' ' << maxn;
    59 }

转载于:https://www.cnblogs.com/ainiyuling/p/11149938.html

[Link 1]: https://www.luogu.org/problemnew/show/P2330