PAT 1018

PAT 1018

题目其实很简单，只要用DFS就可以了，但是我的程序出来5，7两个测试出错，大神看看哪里的问题。

#include <stdio.h>
#define ABS(a) (a>=0?a:-a)
int cmax,nstats,sp,m,min,mintime;
int map[510][510];
int current[510];
int visit[510],road[510],mroad[510];

void dfs(int s,int mtime,int bikes){
	int mt=mtime,bi=bikes,i;
	if(mtime>mintime)
		return;
	if(s==sp ){//到达sp点
		if(mtime<mintime){//路径更短
			min=bikes;
			mintime=mtime;
			for(i=1;i<510;i++)
				mroad[i]=road[i];
		}else if(mtime==mintime){//路径相等
			if(ABS(bikes)<ABS(min)){//哪个需要带更少的车选哪个
				min=bikes;
				for(i=1;i<510;i++)
					mroad[i]=road[i];
			}
		}
		
	}else{
		for(i=1;i<=nstats;i++){
			if(!visit[i] && map[s][i]!=-1){
				visit[i]=1;
				mtime += map[s][i];
				bikes += cmax/2-current[i];
				road[i]=s;
				dfs(i,mtime,bikes);
				mtime = mt;
				bikes = bi;
				visit[i]=0;
			}
		}
	}
}

void printroad(int s){
	if(s==0)
		printf("0");
	else{
		printroad(mroad[s]);
		printf("->%d",s);
	}
}

int main(){
	int i,j;
	int from,to,t;
	for(i=0;i<510;i++){
		visit[i]=0;
		road[i]=mroad[i]=-1;
		for(j=0;j<510;j++)
			map[i][j]=map[j][i]=-1;
	}
	scanf("%d %d %d %d",&cmax,&nstats,&sp,&m);
	for(i=1;i<=nstats;i++)
		scanf("%d",¤t[i]);
	for(i=0;i<m;i++){
		scanf("%d %d %d",&from,&to,&t);
		map[from][to]=map[to][from]=t;
	}
	mintime=min=1000000;
	visit[0]=1;
	dfs(0,0,0);
	if(min>=0){
		printf("%d ",min);
		printroad(sp);
		printf(" 0\n");
	}else{
		printf("0 ");
		printroad(sp);
		printf(" %d\n",-min);
	}
	return 0;
}