SPFA模板

/*
ID: j.sure.1
PROG:
LANG: C++
*/
/****************************************/
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <string>
#include <climits>
#include <iostream>
#define INF 0x3f3f3f3f
using namespace std;
/****************************************/
const int N = 10;
int n, m, tot, head[N], dis[N], fa[N];
bool inq[N];
struct Node
{
    int u, v, w, next;
}edge[N*N];

void init()
{
    memset(head, -1, sizeof(head));
    tot = 0;
}

void add(int u, int v, int w)
{
    edge[tot].u = u;
    edge[tot].v = v;
    edge[tot].w = w;
    edge[tot].next = head[u];
    head[u] = tot++;
}

void spfa(int st)
{
	memset(dis, 0x3f, sizeof(dis));
	memset(inq, 0, sizeof(inq));
    queue <int> q;
    q.push(st);
    dis[st] = 0;
    inq[st] = true;
    while(!q.empty()) {
        int u = q.front();
        q.pop();
        inq[u] = false;
        for(int i = head[u]; i != -1; i = edge[i].next) {
            int v = edge[i].v;
            if(dis[v] > dis[u] + edge[i].w) {
                dis[v] = dis[u] + edge[i].w;
				fa[v] = u;
                if(!inq[v]) {
                    q.push(v);
                    inq[v] = true;
                }
            }
        }
    }
}

int main()
{
#ifdef J_Sure
	freopen("000.in", "r", stdin);
//	freopen(".out", "w", stdout);
#endif
    scanf("%d", &n);
	init();
	int a, b, c;
	while(~scanf("%d%d%d", &a, &b, &c)) {
		if(a == -1&&b == -1 && c == -1) break;
		add(a, b, c);
	}
	spfa(0);
	int dir[N];
	for(int j = 1; j < n; j++) {
		printf("%d\t", dis[j]);
		int cnt = 0, x = j;
		while(x != fa[x]) {
			dir[cnt++] = x;
			x = fa[x];
		}
		dir[cnt] = 0;
		for(int k = cnt; k > 0; k--) {
			printf("%d->", dir[k]);
		}
		printf("%d\n", dir[0]);
	}
    return 0;
}