第一次的代码是我以前打的，是100分

#include <bits/stdc++.h>
using namespace std;
#define N 10001
#define M 500001 
#define P pair<int,int>  
#define Fi first
#define Se second
struct node{
	int to,w,next;
}edge[M];
int cut=0;
int head[N];
int dis[N];
int n,m,k;
bool vis[N];
priority_queue<P,vector<P>,greater<P> > q;
void ini(){
	fill(dis+1,dis+N+1,INT_MAX);
	memset(head,-1,sizeof(head));
}
void add(int u,int v,int w){
	cut++;
	edge[cut].w=w;
	edge[cut].to=v;
	edge[cut].next=head[u];
	head[u]=cut;
}
void Dij(int x){
	dis[x]=0;
	vis[x]=1;
	q.push(P(0,x));
	while(!q.empty()){
		P u=q.top();q.pop();vis[u.Se]=1;
		for(int j=head[u.Se];~j;j=edge[j].next){
			if(!vis[edge[j].to]&&dis[edge[j].to]>dis[u.Se]+edge[j].w){
				dis[edge[j].to]=dis[u.Se]+edge[j].w;
				q.push(P(dis[edge[j].to],edge[j].to));
			}
		}
	}
} 
int main(){
	
	ini();
	scanf("%d %d %d",&n,&m,&k);
	for(int i=1,u,v,w;i<=m;i++){
		scanf("%d %d %d",&u,&v,&w);
		add(u,v,w);
	}
	Dij(k); 
	for(int i=1;i<=n;i++){
		printf("%d ",dis[i]);
	}
		
    return 0;
}

后来又打了一次，感觉没什么区别，却只有30分

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <queue>
#define P pair <int, int>

using namespace std;

template <typename T> inline void fnRead (T& m_In) {
    m_In = 0;
    int m_Flag = 1;
    char m_Ch = getchar ();
    for (; ! isdigit (m_Ch); m_Ch = getchar ()) if (m_Ch == '-') m_Flag = -1;
    for (;   isdigit (m_Ch); m_Ch = getchar ()) m_In = (m_In << 3) + (m_In << 1) + (m_Ch ^ 48);
    m_In *= m_Flag;
}

template <typename T, typename ...Arge> inline void fnRead (T& m_In, Arge&... m_InArge) {
    fnRead (m_In);
    fnRead (m_InArge...);
}

struct edge {
    int m_Next;
    int m_To;
    int m_Data;
}g_Edge[500100];

int g_Cnt = 0;
int g_Head[100100];
int g_Vis[100100];
int g_Dis[100100];
priority_queue <P, vector <P>, greater<P> > g_Queue;

void fnInit () {
    fill (g_Head + 1,g_Head + 110 + 1, -1);
    memset (g_Dis, 0x7f, sizeof (g_Dis));
}

void fnAddEdge (int l_U, int l_V, int l_W) {
    g_Cnt ++;
    g_Edge[g_Cnt].m_Data = l_W;
    g_Edge[g_Cnt].m_To   = l_V;
    g_Edge[g_Cnt].m_Next = g_Head[l_U];
    g_Head[l_U]          = g_Cnt;
}

void fnDij (int l_Begin) {
    g_Dis[l_Begin] = 0;
    g_Vis[l_Begin] = 1;
    g_Queue.push (P (0, l_Begin));
    while (! g_Queue.empty ()) {
        P l_Tmp = g_Queue.top ();
        g_Queue.pop ();
        g_Vis[l_Tmp.second] = 1;
        for (int i = g_Head[l_Tmp.second]; ~i; i = g_Edge[i].m_Next) {
            if (! g_Vis[g_Edge[i].m_To] && g_Edge[i].m_Data + g_Dis[l_Tmp.second] < g_Dis[g_Edge[i].m_To]) {
                g_Dis[g_Edge[i].m_To] = g_Edge[i].m_Data + g_Dis[l_Tmp.second];
                g_Queue.push (P (g_Dis[g_Edge[i].m_To], g_Edge[i].m_To));
            }
        }
    }
}
int main () {

    fnInit();
    int l_PointNumber, l_EdgeNumber, l_Begin;
    fnRead (l_PointNumber, l_EdgeNumber, l_Begin);
    for (int i = 1, l_U, l_V, l_W; i <= l_EdgeNumber; i ++) {
        fnRead (l_U, l_V, l_W);
        fnAddEdge (l_U, l_V, l_W);
    }
    fnDij (l_Begin);
    for (int i = 1; i <= l_PointNumber; i ++) {
        cout << g_Dis[i] << " ";
    }
    cout << endl;

    return 0;
}

求助