poj2421,poj2560,poj1789
这些都是一些比较基础的最小生成树的题目，在这里我分别用两种方法来实现--kruskal以及prim(其中prim是建哥写的,kruskal是我写的).
//poj2421 kruskal #include <iostream> #include<cstdio> #include<algorithm> using namespace std; #define INF 0x3f3f3f3f int n,m; int a[105][105],d; int p[105],xa,yb; int sum,res; typedef struct Node { int value; int l; int r; }; Node edges[105*105]; int find_set(int x) { if(x!=p[x]) p[x]=find_set(p[x]); return p[x]; } bool cmp(Node e1,Node e2) { return e1.value<e2.value; } int main() { scanf("%d",&n); for(int i=1;i<=n;i++) { p[i]=i; } int sym=0,mm=0,m=0; for(int i=1;i<=n;i++) { for(int j=1;j<=n;j++) { scanf("%d",&d); a[i][j]=a[j][i]=d; } } scanf("%d",&mm); for(int i=0;i<mm;i++) { scanf("%d%d",&xa,&yb); a[xa][yb]=0; } for(int i=1;i<n;i++) { for(int j=i+1;j<=n;j++) { edges[m].l=i; edges[m].r=j; edges[m].value=a[i][j]; m++; } } sort(edges,edges+m,cmp); for(int i=0;i<m;i++) { int fx=find_set(edges[i].l); int fy=find_set(edges[i].r); if(fx!=fy) { sum+=edges[i].value; p[fy]=fx; } } printf("%d\n",sum); return 0; } //poj2421 prim #include <stdio.h> #include <string.h> #define INF 0x3f3f3f3f int maps[305][305]; bool vis[305]; int dis[305]; int n; int Prim() { memset(vis,false,sizeof(vis)); for(int i=1; i<=n; i++) dis[i] = INF; int ans=0; dis[1] = 0; for(int i=1; i<=n; i++) { int tmp = INF,k=0; for(int j=1; j<=n; j++) { if(!vis[j]&&dis[j]<tmp) { tmp = dis[j]; k=j; } } vis[k] = true; ans+=tmp; for(int i=1; i<=n; i++) { if(!vis[i]&&dis[i]>maps[k][i]) dis[i] = maps[k][i]; } } return ans; } int main() { while(scanf("%d",&n),n) { for(int i=0; i<=n; i++) { for(int j=0; j<=n; j++) if(i==j) maps[i][j]=0; else maps[i][j] = INF; } for(int i=0; i<n-1; i++) { int t; char a[2],b[2]; scanf("%s%d",a,&t); for(int j=0; j<t; j++) { int dist; scanf("%s%d",b,&dist); maps[a[0]-'A'+1][b[0]-'A'+1] = maps[b[0]-'A'+1][a[0]-'A'+1] = dist; } } printf("%d\n",Prim()); } return 0; } //poj2560 kruskal #include<iostream> #include<cstdio> #include<cmath> #include<algorithm> using namespace std; int t; typedef struct Node { double x; double y; }; typedef struct Edge { int l; int r; double value; }; Edge edges[105*105]; Node node[105]; int p[105],n; double sum; bool cmp(Edge e1,Edge e2) { return e1.value<e2.value; } int find_set(int x) { if(x!=p[x]) p[x]=find_set(p[x]); return p[x]; } int main() { sum=0; scanf("%d",&n); for(int i=1;i<=n;i++) { scanf("%lf%lf",&node[i].x,&node[i].y); p[i]=i; } int m=0; for(int i=1;i<=n;i++) { for(int j=1;j<=n;j++) { double d=sqrt((node[i].x-node[j].x)*(node[i].x-node[j].x)+(node[i].y-node[j].y)*(node[i].y-node[j].y)); edges[m].l=i; edges[m].r=j; edges[m++].value=d; } } sort(edges,edges+m,cmp); /* for(int i=0;i<m;i++) { printf("%lf\n",edges[i].value); }*/ for(int i=0;i<m;i++) { int fx=find_set(edges[i].l); int fy=find_set(edges[i].r); if(fx!=fy) { sum+=edges[i].value; p[fy]=fx; } } printf("%.2lf\n",sum); return 0; } //poj 2560 prim #include <stdio.h> #include <string.h> #include <math.h> #define INF 0x3f3f3f3f int n; double maps[300][300]; bool vis[300]; double dis[300]; struct Point { double x; double y; }points[300]; double Prim() { memset(vis,false,sizeof(vis)); for(int i=1;i<=n;i++) dis[i] = INF; dis[1] = 0; double ans =0; for(int i=1;i<=n;i++) { double tmp = INF; int k =0; for(int j=1;j<=n;j++) { if(!vis[j]&&dis[j]<tmp) { tmp = dis[j]; k= j; } } vis[k]=true; ans+=tmp; for(int i=1;i<=n;i++) { if(!vis[i]&&dis[i]>maps[k][i]) dis[i] = maps[k][i]; } } return ans; } int main() { scanf("%d",&n); for(int i=1;i<=n;i++) scanf("%lf%lf",&points[i].x,&points[i].y); for(int i=1;i<=n;i++) { for(int j=1;j<=n;j++) { double x = points[i].x - points[j].x; double y = points[i].y - points[j].y; maps[i][j] = sqrt(x*x+y*y); } } printf("%.2lf\n",Prim()); return 0; } //poj1789 kruskal #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; int n; char str[2050][10]; int p[2050]; typedef struct Edge { int l; int r; int value; }; bool cmp(Edge e1,Edge e2) { return e1.value<e2.value; } int find_set(int x) { if(x!=p[x]) p[x]=find_set(p[x]); return p[x]; } Edge edges[2050*2050]; int getDif(int x,int y) { int num=0; for(int i=0;i<7;i++) { if(str[x][i]!=str[y][i]) { num++; } } return num; } int main() { while(scanf("%d",&n)&&n!=0) { memset(edges,0,sizeof(edges)); memset(str,0,sizeof(str)); int m=0; for(int i=1;i<=n;i++) { scanf("%s",str[i]); p[i]=i; } for(int i=1;i<=n;i++) { for(int j=i+1;j<=n;j++) { int num=getDif(i,j); edges[m].l=i; edges[m].r=j; edges[m++].value=num; } } sort(edges,edges+m,cmp); int sum=0; for(int i=0;i<m;i++) { int fx=find_set(edges[i].l); int fy=find_set(edges[i].r); if(fx!=fy) { sum+=edges[i].value; p[fy]=fx; } } printf("The highest possible quality is 1/%d.\n",sum); } return 0; } //poj1789 prim #include <stdio.h> #include <string.h> #define INF 0x3f3f3f3f int maps[2005][2005]; char str[2005][2005]; int dis[2005]; bool vis[2005]; int n; int Prim() { memset(vis,false,sizeof(vis)); for(int i=1; i<=n; i++) dis[i] = INF; int ans=0; dis[1] = 0; for(int i=1; i<=n; i++) { int tmp = INF,k=0; for(int j=1; j<=n; j++) { if(!vis[j]&&dis[j]<tmp) { tmp = dis[j]; k=j; } } vis[k] = true; ans+=tmp; for(int i=1; i<=n; i++) { if(!vis[i]&&dis[i]>maps[k][i]) dis[i] = maps[k][i]; } } return ans; } int main() { while(scanf("%d",&n),n) { for(int i=0;i<n;i++) scanf("%s",str[i]); for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { int dist = 0; for(int k=0;k<7;k++) { if(str[i][k]!=str[j][k]) dist++; } maps[i+1][j+1] = dist; } } printf("The highest possible quality is 1/%d.\n",Prim()); } return 0; }