Zoj2326Tangled in Cables

// Zoj2326Tangled in Cables
// Use a rope of a given length to link the house in the village. The house can be regarded as a point.
// There is only one road between each pair of houses. I use Kruscal.
// The zoj platform is powerful ......
// The cmp function defines the return value as an integer. When I return a real number
// (Return (p1-> length-p2-> length) on WA .. Bytes
// If (p1-> length> p2-> length)
// Return 1;
// Else return-1;
// Change it to AC...

#include"stdio.h"#include"string.h"#include"stdlib.h"#define maxint 1000typedef struct point{int s,e;float length;}epoint;epoint side[maxint];int v[maxint];int cmp(const void *a,const void *b){epoint *p1,*p2;p1=(epoint*)a;p2=(epoint*)b;if(p1->length>p2->length)return 1;else return -1;}int find(int i){while(v[i]!=i)i=v[i];return i;}float kruscal(int n,int m){int i,j=0,v1,v2;float sum=0.0;for(i=0;i<m;i++){v1=find(side[i].s);v2=find(side[i].e);if(v1!=v2){sum+=side[i].length;v[v1]=v2;j++;if(j==n-1)break;}}return sum;}int main(){float cable,val,sum;char name[maxint][22],name1[22],name2[22];int n,m,r,c,i,j;while(scanf("%f",&cable)!=EOF){scanf("%d",&n);for(i=0;i<n;i++)scanf("%s",name[i]);scanf("%d",&m);for(i=0;i<m;i++){scanf("%s",name1);scanf("%s",name2);scanf("%f",&val);for(j=0;j<n;j++)if(!strcmp(name1,name[j])){r=j;break;}for(j=0;j<n;j++)if(!strcmp(name2,name[j])){c=j;break;}side[i].e=c;side[i].s=r;side[i].length=val;}for(i=0;i<n;i++)v[i]=i;qsort(side,m,sizeof(epoint),cmp);sum=kruscal(n,m);if(sum>cable)printf("Not enough cable\n");elseprintf("Need %.1f miles of cable\n",sum);}return 0;}