HDU 2544(Floyd、Dijkstra、Bellman-Ford、SPFA)

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中文题
#include <cstdio>#include <cstring>#include <algorithm>#include <queue>#define N 110#define M 10010#define INF 0x3f3f3f3fusing namespace std;struct edgs{    int u, v, dis;}Edgs[M];int dis[N][N], d[N], vis[N];int u[M], v[M], head[M], Next[M], len[M];int n, m, cnt;void add_edgs(int s, int e, int l) {    u[cnt] = s;    v[cnt] = e;    len[cnt] = l;    Next[cnt] = head[s];    head[s] = cnt++;}void init() {    memset(dis, 0x3f, sizeof(dis));    memset(head, -1, sizeof(head));    cnt = 0;    cnt = 0;    int x, y, z;    for (int i = 0; i < m; i++) {        scanf("%d%d%d", &x, &y, &z);        dis[x][y] = dis[y][x] = min(dis[x][y], z);        Edgs[i].u = x;        Edgs[i].v = y;        Edgs[i].dis = min(dis[x][y], z);        add_edgs(x, y, min(dis[x][y], z));        add_edgs(y, x, min(dis[x][y], z));    }}int Dijkstra() {    memset(vis, 0, sizeof(vis));    for (int i = 1; i <= n; i++)        d[i] = INF;    d[1] = 0;    for (int i = 0; i < n; i++) {        int x, t = INF;        for (int j = 1; j <= m; j++)            if (!vis[j] && d[j] < t) {                x = j;                t = d[j];            }        vis[x] = 1;        for (int j = 1; j <= n; j++)            d[j] = min(d[j], d[x] + dis[x][j]);    }    return d[n];}int Floyd() {    for (int i = 1; i <= n; i++)        dis[i][i] = 0;    for (int k = 1; k <= n; k++)        for (int i = 1; i <= n; i++)            for (int j = 1; j <= n; j++)                if (dis[i][k] != INF && dis[k][j] != INF && dis[i][j] > dis[i][k] + dis[k][j])                    dis[i][j] = dis[i][k] + dis[k][j];    return dis[1][n];}int Bellman_Ford() {    for (int i = 2; i <= n; i++)        d[i] = INF;    d[1] = 0;    for (int i = 1; i <= n - 1; i++)         for (int j = 0; j < m; j++) {            int u = Edgs[j].u;            int v = Edgs[j].v;            if (d[u] < INF)                d[v] = min(d[v], d[u] + Edgs[j].dis);            if (d[v] < INF)                d[u] = min(d[u], d[v] + Edgs[j].dis);        }      return d[n];}int SPFA() {    memset(vis, 0, sizeof(vis));    for (int i = 2; i <= n; i++)        d[i] = INF;    d[1] = 0;    queue<int> q;    q.push(1);    while (!q.empty()) {            int t = q.front();        q.pop();        vis[t] = 0;        for (int i = head[t]; i != -1; i = Next[i]) {            if (d[v[i]] > d[u[i]] + len[i]) {                d[v[i]] = d[u[i]] + len[i];                if (!vis[v[i]]) {                    q.push(v[i]);                    vis[v[i]] = 1;                }               }        }    }    return d[n];    }int main() {    while (scanf("%d%d", &n, &m) != EOF && n + m) {        init();//      printf("%d\n", Dijkstra());//      printf("%d\n", Floyd());//      printf("%d\n", Bellman_Ford());        printf("%d\n", SPFA());    }    return 0;}
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