3330061_ac_79ms_944k.cc

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <vector>
#include <queue>
#include <algorithm>
#define max 1001
using namespace std;
 
int INF = 2100000000;

struct Node
{
	int tar;
	int id;
	int value;
};

int N, M;
vector<Node> edge[max];
int dis[max];

struct node
{
	int value;
	int tar;
 
	bool operator<(const node & x) const
	{
		if (value>x.value) return true;
		return false;
	}
};

int num[max];
priority_queue< node ,vector<node> > q;

bool used[max];

void dijk(int start)
{
	int i, j, k;

	while (!q.empty()) q.pop();
 
	for (i = 0; i < N; ++i) dis[i]=INF;
	memset(used,false,sizeof(used));
 
	node temp,temp2;
	temp.value=0;
	temp.tar=start;
	q.push(temp);
 
	while (!q.empty())
	{
		while (!q.empty() && used[q.top().tar]) q.pop();
		if (q.empty()) break;
		temp=q.top();
		q.pop();

		used[temp.tar]=true;
		dis[temp.tar]=temp.value;

		for (k=0;k<edge[temp.tar].size();++k) 
		{
			j=edge[temp.tar][k].tar;
			if (dis[temp.tar]+edge[temp.tar][k].value< dis[j] && !used[j])
			{
				dis[j]=dis[temp.tar]+edge[temp.tar][k].value;
				temp2.tar=j;
				temp2.value=dis[j];
				q.push(temp2);
			}
		}
	}
}

int init()
{
	int i, j, k, l;
 
	scanf("%d",&N);
	if (N==0)
	{
		return 0;
	}
	scanf("%d",&M);
	for (i = 0; i < N; i++)
	{
		edge[i].clear();
	}
	for (i = 0; i < M; ++i)
	{
		scanf("%d%d%d",&j,&k,&l);
		Node t;
		j--;k--;
		t.tar = k;t.value = l;t.id = i+1;
		edge[j].push_back(t);
		t.tar = j;
		edge[k].push_back(t);
	}
	return 1;
}

int dfs(int u)
{
	int i, tmp (0);

	if (num[u]!=-1)
	{
		return num[u];
	}
	for (i = 0; i < edge[u].size(); i++)
	{
		int v = edge[u][i].tar;
		if (dis[u] > dis[v])
		{
			tmp += dfs(v);
		}
	}
	return num[u] = tmp;
}

int main()
{
	int i, j;

	while (init())
	{
		dijk(1);
		memset(num,-1,sizeof(num));
		num[1] = 1;
		printf("%d\n",dfs(0));
	}
	return 0;
}