AC代码1:(Dijkstra,字符映射成数字,跑一遍最短路,简简单单)
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;
public class Main
{
static PrintWriter pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
static int N = (int)200;
static Map<Character,Integer> map = new HashMap<>();
static int g[][] = new int[N][N];
static int dist[] = new int [N];
static boolean visited[] = new boolean[N];
// A~Z映射成1~26
static void reflect()
{
String s = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char str[] = s.toCharArray();
for(int i = 0 ; i < str.length ; i ++) map.put(str[i],i + 1);
}
// 矩阵的初始化
static void init()
{
g[map.get('A')][map.get('B')] = 2;
g[map.get('A')][map.get('C')] = 1;
g[map.get('A')][map.get('D')] = 1;
g[map.get('A')][map.get('E')] = 1;
g[map.get('B')][map.get('A')] = 2;
g[map.get('B')][map.get('G')] = 1;
g[map.get('B')][map.get('J')] = 2;
g[map.get('C')][map.get('A')] = 1;
g[map.get('C')][map.get('D')] = 3;
g[map.get('C')][map.get('G')] = 3;
g[map.get('C')][map.get('F')] = 3;
g[map.get('D')][map.get('C')] = 3;
g[map.get('D')][map.get('A')] = 1;
g[map.get('D')][map.get('E')] = 1;
g[map.get('D')][map.get('I')] = 2;
g[map.get('D')][map.get('H')] = 1;
g[map.get('D')][map.get('G')] = 2;
g[map.get('E')][map.get('A')] = 1;
g[map.get('E')][map.get('D')] = 1;
g[map.get('E')][map.get('H')] = 1;
g[map.get('E')][map.get('I')] = 3;
g[map.get('F')][map.get('C')] = 3;
g[map.get('F')][map.get('J')] = 1;
g[map.get('F')][map.get('G')] = 1;
g[map.get('G')][map.get('F')] = 1;
g[map.get('G')][map.get('B')] = 1;
g[map.get('G')][map.get('C')] = 3;
g[map.get('G')][map.get('D')] = 2;
g[map.get('G')][map.get('I')] = 3;
g[map.get('G')][map.get('K')] = 2;
g[map.get('H')][map.get('D')] = 1;
g[map.get('H')][map.get('E')] = 1;
g[map.get('H')][map.get('I')] = 1;
g[map.get('H')][map.get('L')] = 2;
g[map.get('I')][map.get('M')] = 3;
g[map.get('I')][map.get('G')] = 3;
g[map.get('I')][map.get('H')] = 1;
g[map.get('I')][map.get('D')] = 2;
g[map.get('I')][map.get('E')] = 3;
g[map.get('J')][map.get('B')] = 2;
g[map.get('J')][map.get('F')] = 1;
g[map.get('J')][map.get('S')] = 2;
g[map.get('K')][map.get('G')] = 2;
g[map.get('K')][map.get('L')] = 3;
g[map.get('K')][map.get('P')] = 2;
g[map.get('K')][map.get('N')] = 1;
g[map.get('L')][map.get('H')] = 2;
g[map.get('L')][map.get('M')] = 1;
g[map.get('L')][map.get('R')] = 1;
g[map.get('L')][map.get('K')] = 3;
g[map.get('M')][map.get('S')] = 1;
g[map.get('M')][map.get('Q')] = 1;
g[map.get('M')][map.get('N')] = 2;
g[map.get('M')][map.get('L')] = 1;
g[map.get('M')][map.get('I')] = 3;
g[map.get('N')][map.get('K')] = 1;
g[map.get('N')][map.get('M')] = 2;
g[map.get('N')][map.get('P')] = 1;
g[map.get('O')][map.get('Q')] = 1;
g[map.get('O')][map.get('R')] = 3;
g[map.get('O')][map.get('P')] = 1;
g[map.get('P')][map.get('N')] = 1;
g[map.get('P')][map.get('K')] = 2;
g[map.get('P')][map.get('O')] = 1;
g[map.get('Q')][map.get('O')] = 1;
g[map.get('Q')][map.get('M')] = 1;
g[map.get('R')][map.get('O')] = 3;
g[map.get('R')][map.get('L')] = 1;
g[map.get('R')][map.get('S')] = 1;
g[map.get('S')][map.get('R')] = 1;
g[map.get('S')][map.get('J')] = 2;
g[map.get('S')][map.get('M')] = 1;
}
static int dijstra()
{
Arrays.fill(dist,Integer.MAX_VALUE >> 1);
dist[map.get('A')] = 0;
for(int i = 1 ; i <= 19 ; i ++)
{
int t = -1;
for(int j = 1 ; j <= 19 ; j ++)
{
if(!visited[j] && (t == -1 || dist[j] < dist[t]) ) t = j;
}
visited[t] = true;
for(int j = 1 ; j <= 19 ; j ++) dist[j] = Math.min(dist[j],dist[t] + g[t][j]);
}
if(dist[19] == Integer.MAX_VALUE >> 1) return -1;
return dist[19];
}
public static void main(String[] args ) throws IOException
{
for(int i = 1 ; i < N ; i ++) Arrays.fill(g[i],Integer.MAX_VALUE >> 1);
reflect();
init();
pw.println(dijstra());
pw.flush();
}
}
class rd
{
static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
static StringTokenizer tokenizer = new StringTokenizer("");
static String nextLine() throws IOException { return reader.readLine(); }
static String next() throws IOException
{
while (!tokenizer.hasMoreTokens()) tokenizer = new StringTokenizer(reader.readLine());
return tokenizer.nextToken();
}
static int nextInt() throws IOException { return Integer.parseInt(next()); }
static double nextDouble() throws IOException { return Double.parseDouble(next()); }
static long nextLong() throws IOException { return Long.parseLong(next());}
static BigInteger nextBigInteger() throws IOException
{
BigInteger d = new BigInteger(rd.nextLine());
return d;
}
}
class PII
{
int x,y;
public PII(int x ,int y)
{
this.x = x;
this.y = y;
}
}
AC代码2:(Bellman_ford,直接粗暴加边,不需要映射)
import java.io.*;
import java.math.BigInteger;
import java.util.*;
import java.util.stream.Collectors;
public class Main
{
static PrintWriter pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
static int N = (int)1e3 + 10;
static int INF = 0x3f3f3f3f;
static math math_me = new math();
static List<int []> edges = new ArrayList<>();
static int dist[] = new int[N];
// a到b加一条边,权重为w
static void add(char a, char b, int w)
{
edges.add(new int[] {a, b, w});
edges.add(new int[] {b, a, w});
}
public static void main(String[] args ) throws IOException
{
add('A', 'C', 1);
add('A', 'D', 1);
add('A', 'E', 1);
add('D', 'E', 1);
add('E', 'I', 1);
add('D', 'H', 1);
add('H', 'I', 1);
add('B', 'G', 1);
add('F', 'G', 1);
add('F', 'J', 1);
add('K', 'N', 1);
add('L', 'M', 1);
add('N', 'P', 1);
add('P', 'O', 1);
add('O', 'Q', 1);
add('Q', 'M', 1);
add('L', 'R', 1);
add('S', 'R', 1);
add('M', 'S', 1);
add('A', 'B', 2);
add('B', 'J', 2);
add('D', 'I', 2);
add('D', 'G', 2);
add('G', 'K', 2);
add('K', 'P', 2);
add('J', 'S', 2);
add('M', 'N', 2);
add('H', 'L', 2);
add('E', 'I', 3);
add('I', 'M', 3);
add('G', 'I', 3);
add('C', 'D', 3);
add('C', 'G', 3);
add('C', 'F', 3);
add('O', 'R', 3);
add('K', 'L', 3);
int n = edges.size(); // 边的总数
Arrays.fill(dist,Integer.MAX_VALUE >> 1); // 除以2是为了防止溢出
dist['A'] = 0; // 谁是起点,就把谁的dist(距起点的距离)设置为0,然后利用它来更新邻边,然后邻边可以再更新新的邻边,完美,阿琛yyds
for(int i = 1 ; i <= n - 1 ; i ++) // 迭代(边数-1)次
{
for(int[] edge: edges) // 遍历边的集合中每一条边
{
int a = edge[0],b = edge[1],w = edge[2];
dist[b] = Math.min(dist[b],dist[a] + w); // 更新可以更新的边
}
}
pw.println(dist['S']);
pw.flush();
}
}
class rd
{
static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
static StringTokenizer tokenizer = new StringTokenizer("");
static String nextLine() throws IOException { return reader.readLine(); }
static String next() throws IOException
{
while(!tokenizer.hasMoreTokens()) tokenizer = new StringTokenizer(reader.readLine());
return tokenizer.nextToken();
}
static int nextInt() throws IOException { return Integer.parseInt(next()); }
static double nextDouble() throws IOException { return Double.parseDouble(next()); }
static long nextLong() throws IOException { return Long.parseLong(next()); }
static BigInteger nextBigInteger() throws IOException
{
BigInteger d = new BigInteger(rd.nextLine());
return d;
}
}
class math
{
int gcd(int a,int b)
{
if(b == 0) return a;
else return gcd(b,a % b);
}
int lcm(int a,int b)
{
return a * b / gcd(a, b);
}
// 求n的所有约数
List get_factor(int n)
{
List<Long> a = new ArrayList<>();
for(long i = 1; i <= Math.sqrt(n) ; i ++)
{
if(n % i == 0)
{
a.add(i);
if(i != n / i) a.add(n / i); // // 避免一下的情况:x = 16时,i = 4 ,x / i = 4的情况,这样会加入两种情况 ^-^复杂度能减少多少是多少
}
}
// 相同因子去重,这个方法,完美
a = a.stream().distinct().collect(Collectors.toList());
// 对因子排序(升序)
Collections.sort(a);
return a;
}
// 判断是否是质数
boolean check_isPrime(int n)
{
if(n < 2) return false;
for(int i = 2 ; i <= n / i; i ++) if (n % i == 0) return false;
return true;
}
}
class PII implements Comparable<PII>
{
int x,y;
public PII(int x ,int y)
{
this.x = x;
this.y = y;
}
public int compareTo(PII a)
{
if(this.x-a.x != 0)
return this.x-a.x; //按x升序排序
else return this.y-a.y; //如果x相同,按y升序排序
}
}
class Edge
{
int a,b,c;
public Edge(int a ,int b, int c)
{
this.a = a;
this.b = b;
this.c = c;
}
}
class Line implements Comparable<Line>
{
double k; // 斜率
double b; // 截距
public Line(double k, double b)
{
this.k = k;
this.b = b;
}
@Override
public int compareTo(Line o)
{
if (this.k > o.k) return 1;
if (this.k == o.k)
{
if (this.b > o.b) return 1;
return -1;
}
return -1;
}
}
class mqm
{
int fa[] = new int[1005];
void init()
{
for(int i = 1 ; i <= 1000 ; i ++) fa[i] = i;
}
void merge(int x, int y) { fa[find(x)] = find(y); }
int find(int x)
{
if(x != fa[x]) fa[x] = find(fa[x]);
return fa[x];
}
boolean query(int x, int y) { return find(x) == find(y); }
}