# 单源最短路径

dijkstra(johnson明天更):

#include <bits/stdc++.h>
#define min(x, y) ((x) < (y) ? (x) : (y))
#define max(x, y) ((x) > (y) ? (x) : (y))
#define Fanv(x) for(int i=edge::sum[x-1]+1,now_v=edge::e[i].y;i<=edge::sum[x];i++,now_v=edge::e[i].y)  //For_all_neighbor_vertex 枚举x的所有邻居,now_v=当前枚举的邻居
const int N=100000,M=200000,type=0;//点数，边数最大值(开空间用),有向图type=0，无向图为1
using namespace std;
namespace Fast_IO {
int x(0);
char ch(getchar());
while(ch>'9'||ch<'0')ch=getchar();
while(ch<='9'&&ch>='0') {
x=x*10+ch-'0';
ch=getchar();
}
return x;
}
}
namespace edge {
int n,m,sum[N+1],cnt(0);
struct element {
int x,y,len;//边的起点，终点，边权
bool operator < (const element a)const {
if(x!=a.x)return x<a.x;
else return y<a.y;
}
} e[(1+type)*M+1];
inline void add_edge(int st,int en,int val) {
e[++cnt].x=st;
e[cnt].y=en;
e[cnt].len=val;
}
void work() {
e[0].x=e[0].y=0;
sum[0]=0;
std::sort(e+1,e+cnt+1);
for(int i=1; i<=cnt; i++) {
if(e[i].x!=e[i+1].x) {
sum[e[i].x]=i;
}
}
for(int i=1; i<=n; i++)sum[i]=max(sum[i],sum[i-1]);
}
void reset() {
cnt=0;
}
}
namespace Dijkstra {
int ls(int x) {
return x<<1;
}
int rs(int x) {
return (x<<1)+1;
}
int INF(1e9+1),start,ans[4*N+5],ans_pos[4*N+5],dis[N+1],b[N+1],n,m;
void push_up(int id) {
if(ans[ls(id)]<=ans[rs(id)]) {
ans[id]=ans[ls(id)];
ans_pos[id]=ans_pos[ls(id)];
} else {
ans[id]=ans[rs(id)];
ans_pos[id]=ans_pos[rs(id)];
}
}
void build(int l,int r,int id) {
if(l==r) {
if(l!=start)ans[id]=INF;
else ans[id]=0;
ans_pos[id]=l;
return;
}
int mid((l+r)>>1);
build(l,mid,ls(id));
build(mid+1,r,rs(id));
push_up(id);
return;
}
void opc(int pos,int l,int r,int id,long long int zhi,int type) {
if(l==r) {
if(type)ans[id]=min(ans[id],zhi);
else ans[id]=zhi;
return;
}
int mid((l+r)>>1);
if(pos<=mid)opc(pos,l,mid,ls(id),zhi,type);
else opc(pos,mid+1,r,rs(id),zhi,type);
push_up(id);
return;
}
void Solve(int n) {
build(1,n,1);
int T=n;
//		dis[start]=0;
while(T--) {
int now=ans_pos[1],now_len=ans[1];
dis[now]=now_len;
b[now]=1;
opc(now,1,n,1,INF,0);
Fanv(now) {
if(!b[now_v]&&now_v!=now) {
opc(now_v,1,n,1,now_len+edge::e[i].len,1);
}
}
}
}
void reset() {
memset(b,0,sizeof(b));
}
}
int main() {
for(int i=1; i<=edge::m; i++) {
int x,y,len;