2.1
2.1
P1144 最短路计数 - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
- 用java会吃T，java底层没有加速这道题会被卡常数
- 本质上就是用bfs来进行搜索每个点与点1的最近距离，然后维护两个数组来计算路径条数，其实就是一个spfa算法的实现
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
import java.util.*;
public class Main implements Runnable {
static StreamTokenizer cin = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
static PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));
static int n, m;
static final int N = (int) (1e6 + 10);
static Vector<Integer>[] node = new Vector[N];
static Queue<Integer> queue = new LinkedList<>();
static int[] dist = new int[N];
static int[] ans = new int[N];
static boolean[] str = new boolean[N];
public static void main(String[] args) {
new Thread(null, new Main(), "", 1 << 29).start();
}
public static int nextInt() throws IOException {
cin.nextToken();
return (int) cin.nval;
}
public static void bfs() {
while(!queue.isEmpty()) {
int val = queue.poll();
for (Integer i : node[val]) {
if(dist[val] == dist[i] + 1 && str[i]) {
ans[val] += ans[i];
ans[val] %= 100003;
}
}
for (Integer num : node[val]) {
if(!str[num]) {
str[num] = true;
queue.add(num);
dist[num] = dist[val] + 1;
}
}
}
}
@Override
public void run() {
try {
for (int i = 0; i < N; i++) node[i] = new Vector<>();
n = nextInt();m = nextInt();
for (int i = 1; i <= m; i++) {
int x = nextInt();int y = nextInt();
if(x == y) continue;
node[x].add(y);node[y].add(x);
}
queue.add(1);str[1] = true;dist[1] = 0;ans[1] = 1;
bfs();
// for (int i = 1; i <= n; i++) System.out.print(dist[i] + " ");
// System.out.println();
for (int i = 1; i <= n; i++) cout.println(ans[i]);
cout.flush();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
#include<iostream>
#include<cstring>
#include<vector>
#include<queue>
using namespace std;
const int N = 1e6 + 10;
vector<int> node[N];
queue<int>q;
int dist[N];
int ans[N];
bool str[N];
int n, m;
void bfs() {
while(q.size()) {
int val = q.front();
q.pop();
for (int i : node[val]) {
if(dist[val] == dist[i] + 1 && str[i]) {
ans[val] += ans[i];
ans[val] %= 100003;
}
}
for (int num : node[val]) {
if(!str[num]) {
str[num] = true;
q.push(num);
dist[num] = dist[val] + 1;
}
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin>>n>>m;
for (int i = 1; i <= m; i++) {
int x, y;
cin>>x>>y;
if(x == y) continue;
node[x].push_back(y);node[y].push_back(x);
}
q.push(1);str[1] = true;dist[1] = 0;ans[1] = 1;
bfs();
for (int i = 1; i <= n; i++) cout<<ans[i]<<endl;
return 0;
}
Dungeon Master - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
- 感觉没啥问题，就是加了两个方向然后多了一个维度而已，但是总是WA，求调
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.*;
public class Main implements Runnable {
static Scanner scanner = new Scanner(System.in);
// static BufferedReader cin = new BufferedReader(new InputStreamReader(System.in));
static PrintWriter cout = new PrintWriter(new OutputStreamWriter(System.out));
static int[] dx = {0, 1, 0, -1, 0, 0, 0};
static int[] dy = {0, 0, 1, 0, -1, 0, 0};
static int[] dz = {0, 0, 0, 0, 0, 1, -1};
static int l, r, c, ans = 0;
static final int N = 30;
static char[][][] g = new char[N][N][N];
static boolean[][][] str = new boolean[N][N][N];
static int[][][] dist = new int[N][N][N];
static Queue<node>queue = new LinkedList<>();
public static void main(String[] args) {
new Thread(null, new Main(), "", 1 << 29).start();
}
public static void bfs() {
while(!queue.isEmpty()) {
node t = queue.poll();
for(int i = 1; i <= 6; i++) {
int nowx = dx[i] + t.x;int nowy = dy[i] + t.y;int nowz = dz[i] + t.z;
if (nowx < 1 || nowx > r || nowy < 1 || nowy > c || nowz < 1 || nowz > l || str[nowz][nowx][nowy] || g[nowz][nowx][nowy] == '#') continue;
dist[nowz][nowx][nowy] = dist[t.z][t.x][t.y] + 1;
if (g[nowz][nowx][nowy] == 'E'){
ans = dist[nowz][nowx][nowy];
cout.println("Escaped in " + ans + " minute(s).");
return;
}
str[nowz][nowx][nowy] = true;
queue.add(new node(nowx, nowy, nowz));
}
}
cout.println("Trapped!");
}
// public static void dfs(int z, int x, int y, int cnt) {
// if(g[z][x][y] == 'E'){
// ans = Math.min(cnt, ans);
// return;
// }
// if(ans <= cnt) return;
//
// for(int i = 1; i <= 6; i++) {
// int nowx = dx[i] + x;int nowy = dy[i] + y;int nowz = dz[i] + z;
// if (nowx < 1 || nowx > r || nowy < 1 || nowy > c || nowz < 1 || nowz > l || str[nowz][nowx][nowy] || g[nowz][nowx][nowy] == '#') continue;
// str[nowz][nowx][nowy] = true;
// dfs(nowz, nowx, nowy, cnt + 1);
// str[nowz][nowx][nowy] = false;
// }
// }
@Override
public void run() {
l = scanner.nextInt();r = scanner.nextInt();c = scanner.nextInt();
while(l != 0 && r != 0 && c != 0) {
int startX = 0, startY = 0, startZ = 0;
for(int i = 1; i <= l; i++) {//z
for(int j = 1; j <= r; j++) {//x
String s = scanner.next();
for(int k = 0; k < s.length(); k++){//y
if (s.charAt(k) == 'S') {
startZ = i;startX = j;startY = k + 1;
}
g[i][j][k + 1] = s.charAt(k);
}
}
}
queue.add(new node(startX, startY, startZ));
str[startZ][startX][startY] = true;
bfs();
ans = 0;
l = scanner.nextInt();r = scanner.nextInt();c = scanner.nextInt();
for (int i = 1; i <= l; i++) {
for (int j = 1; j <= r; j++) {
Arrays.fill(str[i][j], false);
Arrays.fill(g[i][j], '0');
}
}
queue.clear();
}
cout.flush();
}
static class node {
public int x;
public int y;
public int z;
public node(int x, int y, int z) {
this.x = x;
this.y = y;
this.z = z;
}
}
}
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