标签:iaccepted 并查集 最小生成树 hdu 1102
3 0 990 692 990 0 179 692 179 0 1 1 2
179
思路就是构造一棵最小生成树,所以将距离排序,从小到大依次并入,直到集合数为1为止。
#include <cstdio> #include <cstdlib> #include <vector> #include <algorithm> using namespace std; const int MAXX = 102; typedef struct Road{ int x, y, dist; Road(int ix, int iy, int idist){ x = ix; y = iy; dist = idist; } }road; int n,roads,length; vector<road> vec; int pre[MAXX]; bool yes[MAXX][MAXX] = { 0 }; void init(int n){ for (int i = 1; i <= n; ++i){ pre[i] = i; } } int root(int x){ if (x != pre[x]){ pre[x] = root(pre[x]); } return pre[x]; } bool merge(int x, int y){ int fy = root(y); int fx = root(x); bool mark = false; if (fx != fy){ pre[fx] = fy; mark = true; --roads; } return mark; } bool cmp(road a, road b){ return a.dist < b.dist; } int main(){ //freopen("in.txt", "r", stdin); int dist, t, x, y; while (scanf("%d", &n) != EOF){ roads = n - 1; vec.clear(); memset(yes, 0, sizeof(yes)); for (int i = 1; i <= n; ++i){ for (int j = 1; j <= n; ++j){ scanf("%d", &dist); if (i == j || i > j)continue;//重复的路径不进行添加 vec.push_back(road(i, j, dist)); } } sort(vec.begin(), vec.end(), cmp); init(n); scanf("%d", &t); while (t--){ scanf("%d %d", &x, &y); merge(x, y); yes[x][y] = true; } length = 0; vector<road>::iterator ite = vec.begin(); for (; ite != vec.end() && roads != 0; ++ite){ x = (*ite).x; y = (*ite).y; dist = (*ite).dist; if (yes[x][y])continue; if (merge(x, y))length += dist; } printf("%d\n", length); } return 0; }
HDU 1102 Constructing Roads (裸的并查集),布布扣,bubuko.com
HDU 1102 Constructing Roads (裸的并查集)
标签:iaccepted 并查集 最小生成树 hdu 1102
原文地址:http://blog.csdn.net/iaccepted/article/details/29220347