One of the SPFA algorithm implementations

Problem Description:
Given an n vertex, the forward graph of the M-Edge (some of which may be negative, but no negative ring is guaranteed). Please calculate the shortest path from point 1th to other points (vertices are numbered from 1 to n).

Input format:
First line two integers n, M.
The next M-line, each line has three integers u, V, L, indicating that u to V has an edge of length L.

Output format:
A total of n-1 lines, line I represents the shortest path from point No. 1th to I+1.

Sample input:
7 ·
1 2-1
2 3-1
3 1 2

Sample output:
-1
-2

Data size and conventions:
For 10% of data, n = 2,m = 2.
For 30% of data, n <= 5,m <= 10.
For 100% of data, 1 <= n <= 20000,1 <= m <= 200000,-10000 <= L <= 10000, guaranteeing that all vertices can be reached from any vertex.

?

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465 666768697071727374757677787980818283848586878889909192

#include <stdio.h>#include <queue>#include <string.h>#define Infinite 210000000#define ListEndFlag  -1intnumber_vertex;intnumber_edge;int dist[20010];inthead[20010];struct{    intto, w, next;}edge[200010];voidSPFA(){    // 用于标识顶点是否在队列中    bool isAlreadyInQueue[20010];    // 初始化数据    for(inti = 2; i <= number_vertex; i++)    {        dist[i] = Infinite;        isAlreadyInQueue[i] = false;    }    dist[1] = 0;    isAlreadyInQueue[1] = true;    std::queue<int> q;    q.push(1);    while(q.empty() == false)    {        constintx = q.front();        for (inti = head[x]; i != ListEndFlag; i = edge[i].next)        {            constinty = edge[i].to;            constint w = edge[i].w;            if(dist[x] + w < dist[y])            {                dist[y] = dist[x] + w;                if (isAlreadyInQueue[y] == false)                {                    q.push(y);                    isAlreadyInQueue[y] = true;                }            }        }        q.pop();        isAlreadyInQueue[x] = false;    }}intmain(){    // 1. 读取顶点数，边数    scanf("%d%d", &number_vertex, &number_edge);    // 2. 设置 flag    memset(head, ListEndFlag, sizeof(head));    // 3. 读取边    for(inti = 1; i <= number_edge; i++)    {        int x, y, w;        scanf("%d%d%d", &x, &y, &w);        edge[i].to   = y;        edge[i].w    = w;        edge[i].next = head[x];         head[x]      = i;    }    // 4. 执行 SPFA    SPFA();    // 5. 输出结果    for(int i = 2; i <= number_vertex; i++)    {        printf("%d\n", dist[i]);    }    return0;}

One of the SPFA algorithm implementations