3 条题解

  • 0
    @ 2022-1-22 22:25:08

    友情提示: 该题须开long long,且对设置的INF有较大要求,须开到极大

    #include<bits/stdc++.h>
    #define MaxN 100010
    #define MaxM 500010
    #define ll long long
    #define inf 114514191981019260817
    using namespace std;
    struct edge
    {
        ll to, dis, next;
    };
    edge e[MaxM];
    ll head[MaxN], dis[MaxN], cnt;
    bool vis[MaxN];
    ll n, m, s;
    inline void add_edge( int u, int v, int d )
    {
        cnt++;
        e[cnt].dis = d;
        e[cnt].to = v;
        e[cnt].next = head[u];
        head[u] = cnt;
    }
    struct node
    {
        ll dis;
        ll pos;
        bool operator <( const node &x )const
        {
            return x.dis < dis;
        }
    };
    priority_queue < node > q;
    inline void dijkstra()
    {
        dis[s] = 0;
        q.push( ( node ){0, s} );
        while( !q.empty() )
        {
            node tmp = q.top();
            q.pop();
            int x = tmp.pos, d = tmp.dis;
            if( vis[x] )
                continue;
            vis[x] = 1;
            for(ll i = head[x]; i; i = e[i].next)
            {
                ll y = e[i].to;
                if( dis[y] > dis[x] + e[i].dis )
                {
                    dis[y] = dis[x] + e[i].dis;
                    if( !vis[y] )
                    {
                        q.push( ( node ){dis[y], y} );
                    }
                }
            }
        }
    }
    int main()
    {
        scanf( "%lld%lld%lld", &n, &m, &s );
        for(int i = 1; i <= n; ++i) dis[i] = inf;
        for(ll i = 0; i < m; ++i )
        {
            ll u, v, d;
            scanf( "%lld%lld%lld", &u, &v, &d );
            add_edge( u, v, d );
        }
        dijkstra();
        for( int i = 1; i <= n; i++ )
            printf( "%lld ", dis[i] );
        return 0;
    }
    

    信息

    ID
    223
    时间
    1000ms
    内存
    256MiB
    难度
    7
    标签
    (无)
    递交数
    313
    已通过
    67
    上传者