Codevs 1079 回家 最短路 spfa || dijkstra

Codevs 1079 回家 最短路

直接利用 ASCII 码把字母转化为顶点跑最短路就可以了，
如果嫌我的方法浪费了部分空间 可以令 把所有的 ASCII 都-‘A’；

spfa

#include <iostream>#include <cstdio>#include <queue>#include <cstring>#define MAX_V 200#define MAX_E (10000+10)using namespace std;int E, tot = 0;int first[MAX_V], nxt[MAX_E << 1], dis[MAX_V];bool used[MAX_V];struct edge{    int from, to, cost;}es[MAX_E << 1];void build(int ff, int tt, int dd){    es[++tot] = (edge){ff,tt,dd};    nxt[tot] = first[ff];    first[ff] = tot;}queue <int> q;void spfa(int s){    memset(dis,63,sizeof(dis));    dis[s] = 0;    q.push(s);    used[s] = 1;    while(q.size())    {        int x = q.front();        q.pop();        used[x] = 0;        for(int i = first[x]; i != -1; i = nxt[i])        {            int v = es[i].to;            if(dis[v] > dis[x] + es[i].cost)            {                dis[v] = dis[x] + es[i].cost;                if(!used[v])                {                    q.push(v);                    used[v] = 1;                }            }        }    }}int deal(char c){    return (int)(c);}char s[2];int main(){    cin >> E;    memset(first,-1,sizeof(first));    for(int i = 1; i <= E; i ++)    {        int f, t, d;        scanf("%s", s); f = deal(s[0]);        scanf("%s", s); t = deal(s[0]);        scanf("%d", &d);        build(f,t,d); build(t,f,d);    }    spfa(deal('Z'));    int minn = 1e9, ans;    for(int i = deal('A'); i < deal('Z'); i ++)        if(dis[i] < minn)        {            minn = dis[i];            ans = i;        }    cout << (char)ans << " " << minn << endl;    return 0;}

dijkstra

#include <iostream>#include <cstdio>#include <queue>#include <cstring>#define MAX_V 200#define MAX_E (10000+10)using namespace std;int E, tot = 0;int first[MAX_V], nxt[MAX_E << 1], dis[MAX_V];bool done[MAX_V];struct edge{    int from, to, cost;}es[MAX_E << 1];void build(int ff, int tt, int dd){    es[++tot] = (edge){ff,tt,dd};    nxt[tot] = first[ff];    first[ff] = tot;}struct zt{    int v, d;    bool operator < (const zt b) const    {        return d > b.d;    }};priority_queue <zt> q;void dijkstra(int s){    memset(dis,63,sizeof(dis));    dis[s] = 0;    q.push((zt){s,dis[s]});    while(q.size())    {        int x = q.top().v;        q.pop();        if(done[x]) continue;        done[x] = 1;        for(int i = first[x]; i != -1; i = nxt[i])        {            int v = es[i].to;            if(dis[v] > dis[x] + es[i].cost)            {                dis[v] = dis[x] + es[i].cost;                q.push((zt){v,dis[v]});            }        }    }}int deal(char c){    return (int)(c);}char s[2];int main(){    cin >> E;    memset(first,-1,sizeof(first));    for(int i = 1; i <= E; i ++)    {        int f, t, d;        scanf("%s", s); f = deal(s[0]);        scanf("%s", s); t = deal(s[0]);        scanf("%d", &d);        build(f,t,d); build(t,f,d);    }    dijkstra(deal('Z'));    int minn = 1e9, ans;    for(int i = deal('A'); i < deal('Z'); i ++)        if(dis[i] < minn)        {            minn = dis[i];            ans = i;        }    cout << (char)ans << " " << minn << endl;    return 0;}