标签：hdu4009
2 10 20 30 1 3 2 2 4 1 1 2 2 1 2 0 0 0 0
30HintIn 3‐dimensional space Manhattan distance of point A (x1, y1, z1) and B(x2, y2, z2) is |x2‐x1|+|y2‐y1|+|z2‐z1|.
题解：水源可以看作从虚拟根节点引出来的，这道题必定有解，因为大不了每个实际点都跟根节点相连嘛，所以ZL_MST函数里的判断非根无入边节点可以忽略掉。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#define maxn 1002
#define maxm 1000002
int X, Y, Z;
struct Node{
int x, y, z;
} ver[maxn];
struct Node2{
int u, v, cost;
} E[maxm];
int in[maxn], hash[maxn], vis[maxn], pre[maxn];
int calDist(Node a, Node b){
return abs(a.x - b.x) + abs(a.y - b.y) + abs(a.z - b.z);
}
__int64 ZL_MST(int root, int nv, int ne)
{
__int64 ans = 0;
int u, v, i, cnt;
while(true){
//0.初始化
for(i = 0; i < nv; ++i) in[i] = INT_MAX;
//1.找最小入边集
for(i = 0; i < ne; ++i){
u = E[i].u; v = E[i].v;
if(E[i].cost < in[v] && u != v){
in[v] = E[i].cost; pre[v] = u;
}
}
//2.找非根无入边点(略)，因为必定有解
//3.找环，加权，重新标号
memset(hash, -1, sizeof(hash));
memset(vis, -1, sizeof(vis));
cnt = in[root] = 0;
for(i = 0; i < nv; ++i){
ans += in[i]; v = i;
while(vis[v] != i && v != root && hash[v] == -1){
vis[v] = i; v = pre[v];
}
if(v != root && hash[v] == -1){
for(u = pre[v]; u != v; u = pre[u])
hash[u] = cnt;
hash[v] = cnt++;
}
}
if(cnt == 0) return ans; //无环，算法完成
for(i = 0; i < nv; ++i)
if(hash[i] == -1) hash[i] = cnt++;
//4.缩点，遍历每一条边，重新构图
for(i = 0; i < ne; ++i){
v = E[i].v;
E[i].u = hash[E[i].u];
E[i].v = hash[E[i].v];
if(E[i].u != E[i].v) E[i].cost -= in[v];
}
//顶点数减少
nv = cnt; root = hash[root];
}
return ans;
}
int main()
{
int n, i, a, b, id;
while(scanf("%d%d%d%d", &n, &X, &Y, &Z) != EOF && (n||X||Y||Z)){
for(i = 0; i < n; ++i)
scanf("%d%d%d", &ver[i].x, &ver[i].y, &ver[i].z);
for(i = id = 0; i < n; ++i){
scanf("%d", &a);
while(a--){
scanf("%d", &b);
E[id].cost = calDist(ver[i], ver[--b]) * Y;
if(ver[b].z > ver[i].z) E[id].cost += Z;
E[id].u = i; E[id++].v = b;
}
}
for(i = 0; i < n; ++i){
E[id].u = n; E[id].v = i;
E[id++].cost = ver[i].z * X;
}
printf("%I64d\n", ZL_MST(n, n + 1, id));
}
return 0;
}HDU4009 Transfer water 【最小树形图】,布布扣,bubuko.com
HDU4009 Transfer water 【最小树形图】
标签：hdu4009
原文地址：http://blog.csdn.net/chang_mu/article/details/38453595
