【最小生成树】Arctic Network POJ - 2349
作者:互联网
Arctic Network POJ - 2349
题意:
给定\(n\)个互不相同的长度为\(7\)的字符串,将两个字符串之间的距离定义为两串中字符不同的位置个数,问\(1/Q\)的最大值,其中\(Q=\sum^{t_d}_{t_0}{d({t_0},{t_d})}\)。
思路:
求的就是最小生成树的总边权……除了距离需要另外算一下以外就是套模板。
const int maxn = 2000 + 100;
const int maxm = 4000000 + 100;
int fa[maxn], tmp[maxm];
int u[maxm], v[maxm];
int w[maxm];
int n, m;
string s[maxn];
int find(int x) {
return fa[x] == x ? x : fa[x] = find(fa[x]);
}
bool cmp(int i, int j) {
return w[i] < w[j];
}
int count(string s1, string s2) {
int a = 0;
for (int i = 0; i < 7; i++) {
if (s1[i] != s2[i]) a++;
}
return a;
}
double solve() {
int ans = 0;
for (int i = 0; i < maxn; i++) fa[i] = i;
for (int i = 0; i < m; i++) tmp[i] = i;
sort(tmp, tmp + m, cmp);
for (int i = 0; i < m; i++) {
int e = tmp[i];
int from = find(u[e]);
int to = find(v[e]);
if (from != to) {
ans += w[e];
fa[from] = to;
}
}
return ans;
}
int main()
{
//ios::sync_with_stdio(false);
while (cin >> n && n) {
m = 0;
for (int i = 1; i <= n; i++) {
cin >> s[i];
for (int j = i - 1; j >= 1; j--) {
int k = count(s[i], s[j]);
u[m] = i; v[m] = j; w[m] = k; m++;
u[m] = j; v[m] = i; w[m] = k; m++;
}
}
cout << "The highest possible quality is 1/" << solve() << "." << endl;
}
return 0;
}
标签:tmp,return,Network,fa,int,Arctic,2349,++,maxm 来源: https://www.cnblogs.com/streamazure/p/13503646.html