P4779 【模板】单源最短路径（标准版）

P4779 【模板】单源最短路径（标准版）

求单源最短路， 输出距离

Solution

\(nlogn\) 堆优化 \(Djs\)

Code

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<algorithm>
typedef long long LL;
using namespace std;
LL RD(){
    LL out = 0,flag = 1;char c = getchar();
    while(c < '0' || c >'9'){if(c == '-')flag = -1;c = getchar();}
    while(c >= '0' && c <= '9'){out = out * 10 + c - '0';c = getchar();}
    return flag * out;
    }
const LL maxn = 1000019,INF = 0xfffffffffffffff;
LL head[maxn],nume = 1;
struct Node{
    LL v,dis,nxt;
    }E[maxn << 3];
void add(LL u,LL v,LL dis){
    E[++nume].nxt = head[u];
    E[nume].v = v;
    E[nume].dis = dis;
    head[u] = nume;
    }
LL num, nr, s;
bool vis[maxn];
LL d[maxn];
struct node{
	LL u, d;
	bool operator < (const node &a)const{
		return d > a.d;
		}
	};
void Djs(LL s){
	for(LL i = 1;i <= num;i++)d[i] = INF;
	priority_queue<node>Q;
	d[s] = 0;
	Q.push((node){s, d[s]});
	while(!Q.empty()){
		LL u = Q.top().u;Q.pop();
		if(vis[u])continue;
		vis[u] = 1;
		for(LL i = head[u];i;i = E[i].nxt){
			LL v = E[i].v, dis = E[i].dis;
			if(d[u] + dis < d[v]){
				d[v] = d[u] + dis;
				Q.push((node){v, d[v]});
				}
			}
		}
	}
int main(){
	num = RD();nr = RD();s = RD();
	for(int i = 1;i <= nr;i++){
		LL u = RD(), v = RD(), dis = RD();
		add(u, v, dis);
		}
	Djs(s);
	for(int i = 1;i <= num;i++)printf("%lld ", d[i]);
	return 0;
	}