【图】单源最短路径dijkstra

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<cstdlib>
using namespace std;
const int INF = 1000000000;
const int MAXN = 1000;

int n, m;
int v[MAXN], d[MAXN], G[MAXN][MAXN];

int main() {
scanf("%d%d", &n, &m);
for(int i = 0; i < n; i++)
for(int j = 0; j < n; j++)
G[i][j] = INF;
for(int i = 0; i < m; i++) {
int u, v, w;
scanf("%d%d%d", &u, &v, &w);
G[u][v] = w;
}

memset(v, 0, sizeof(v));
for(int i = 0; i < n; i++) d[i] = (i==0 ? 0 : INF);
for(int i = 0; i < n; i++) {
int x, m = INF;
for(int y = 0; y < n; y++) if(!v[y] && d[y]<=m) m = d[x=y]; //选出所有未被遍历的点中d值最小的节点x，即到始点最短的点
v[x] = 1;//标记点x
for(int y = 0; y < n; y++) d[y] = min(d[y], d[x] + G[x][y]);//更新
}

for(int i = 0; i < n; i++)
printf("d[%d] =  %d\n", i, d[i]);
return 0;
}

struct Edge
{
int from,to,dist
}

struct HeapNode
{
int d,u;//d是距离，u是节点号
bool operator < (const HeapNode& rhs) const
{
return d>rhs.d;
}
};

struct Dijkstra
{
int n,m;//vertices and edges
vector<Edge> edges;
vector<int> G[maxn];
bool done[maxn];
int d[maxn];
int p[maxn];

void init(int n)
{
this->n=n;
for(int i=0;i<n;i++) G[i].clear();
edges.clear();
}

void AddEdge(int from,int to,int dist)
{
edges.push_back((Edge){from,to,dist});
m=edges.size();
G[from].push_back(m-1);
}

void dijkstra(int s)
{
priority_queue<HeapNode> Q;//有限队列优化
for(int i=0;i<n;i++) d[i]=INF;//初始化
d[s]=0;
memset(done,0,sizeof(done));

Q.push((HeapNode){0,s});//把节点压栈开始
while(!Q.empty())//当队列非空
{
HeapNode x=Q.top();//队首元素
Q.pop();//弹出
int u=x.u;
if(done[u]) continue;

done[u]=true;
for(i=0;i<G[u].size();i++)//遍历所有的边
{
Edge& e=edges[G[u][i]];
if(d[e.to]>d[u]+e.dist)
{
d[e.to]=d[u]+e.dist;
p[e.to]=G[u][i];
Q.push((HeapNode){d[e.to],e.to});
}
}
}
}
}

#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
//terraria
const int INF = 1000000000;
const int MAXN = 1000;
const int MAXM = 100000;

int n, m;
int first[MAXN], d[MAXN];
int u[MAXM], v[MAXM], w[MAXM], next[MAXM];

typedef pair<int,int> pii;

int main(void)
{//读入及初始化
scanf("%d%d", &n, &m);
for(int i = 0; i < n; i++) first[i] = -1;
for(int e = 0; e < m; e++) {
scanf("%d%d%d", &u[e], &v[e], &w[e]);
next[e] = first[u[e]];
first[u[e]] = e;
}

priority_queue<pii, vector<pii>, greater<pii> > q;//优先队列
//bool done[MAXN];
for(int i = 0; i < n; i++) d[i] = (i==0 ? 0 : INF);//将所有非0值置为最大
//memset(done, 0, sizeof(done));
q.push(make_pair(d[0], 0));
while(!q.empty()) {
pii u = q.top(); q.pop();
int x = u.second;
if(x==3) printf("3 occurs, u.first=%d, d[3]=%d\n", u.first, d[3]);
if(u.first != d[x]) {printf("node #%d: first=%d, d[x]=%d, continue\n", x,u.first,d[x]); continue;}
//done[x] = true;
if(x==3) printf("3 using, d[3] = %d\n", d[3]);
for(int e = first[x]; e != -1; e = next[e]) if(d[v[e]] > d[x]+w[e]) {

d[v[e]] = d[x] + w[e];
q.push(make_pair(d[v[e]], v[e]));
printf("%d kuozhanle %d, d=%d\n",x, v[e], d[v[e]]);
}
}

for(int i = 0; i < n; i++)
printf("d[%d] = %d\n", i, d[i]);
while(1);
return 0;
}