hdu 5876 Sparse Graph icpc大连站网络赛 1009 补图最短路

 BFS+链表

代码改自某博客

#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<math.h>
#include<string.h>
#include<string>
#include<map>
#include<set>
#include<vector>
#include<queue>
using namespace std;
const int maxn = 2e5+5;
const int INF  = 0x3f3f3f3f;
const int A=INF;
const int B=1;
typedef long long LL;
int h[maxn],e;
LL dis[maxn];
bool vis[maxn];
int start;

struct Edge
{
    int v,nxt,w;
} E[maxn<<1];

void init()
{
    e=0;
    memset(h,-1,sizeof h);
    memset(vis,false,sizeof vis);
}

void add(int u,int v,int w)
{
    E[e].v = v;
    E[e].w = w;
    E[e].nxt = h[u];
    h[u]  = e++;
}

struct QNode
{
    int v,c;
    QNode(int _v,int _c)
    {
        v = _v;
        c=_c;
    }
    bool operator < (const QNode &a) const
    {
        return c>a.c;
    }
};

void dijkstra(int n)
{
    memset(dis,INF,sizeof dis);
    priority_queue<QNode>Q;
    dis[1] = 0;
    Q.push(QNode(1,0));
    while(!Q.empty())
    {
        QNode tmp = Q.top();
        Q.pop();
        int u = tmp.v;
        if(vis[u]) continue;
        vis[u] = true;
        for(int i=h[u]; ~i; i=E[i].nxt)
        {
            int v = E[i].v;
            int w = E[i].w;
            if(vis[v]) continue;
            if(dis[u]+w<dis[v])
            {
                dis[v] = dis[u]+w;
                Q.push(QNode(v,dis[v]));
            }
        }
    }
}

void BFS(int n,LL val)
{
    set<int>ta,tb;
    queue<int>Q;
    Q.push(start);
    dis[start] = 0,dis[n] = INF;
    for(int i=1; i<=n; i++){
        if(i==start) continue;
        ta.insert(i);
    }
    while(!Q.empty())
    {
        int u = Q.front();
        Q.pop();
        for(int i=h[u]; ~i; i=E[i].nxt)
        {
            int v = E[i].v;
            if(!ta.count(v)) continue;
            ta.erase(v);
            tb.insert(v);
        }
        for(set<int>::iterator it=ta.begin(); it!=ta.end(); it++)
        {
            Q.push(*it);
            dis[*it] = dis[u] + val;
        }
        ta.swap(tb);
        tb.clear();
    }
}

int main()
{
    int N,M,T;
    int u,v;
    while(scanf("%d",&T)!=EOF)
    {
        while(T--)
        {
            scanf("%d%d",&N,&M);
            init();
            bool flag = false;
            for(int i=0; i<M; i++)
            {
                scanf("%d%d",&u,&v);
                add(u,v,A);
                add(v,u,A);

            }
            scanf("%d",&start);
            dijkstra(N);
            BFS(N,B);
            bool first=0;
            for(int i=1;i<=N;i++)
            {
                if(i==start) continue;
                if(first) printf(" ");
                printf("%d",dis[i]);
                first=1;
            }
            printf("
");
        }
    }
    return 0;
}


/*

1
2 0
1

*/