57 lines
1.7 KiB
Java
57 lines
1.7 KiB
Java
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package leet.book.queueStack;
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import java.util.Arrays;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Queue;
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/**
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* Created with IntelliJ IDEA.
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*
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* @author: 轩辕龙儿
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* @date: 2021/7/2 10:46
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* @Description: No Description
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*/
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public class WallsAndGates {
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class Solution {
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private static final int EMPTY = Integer.MAX_VALUE;
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private static final int GATE = 0;
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private final List<int[]> DIRECTIONS = Arrays.asList(
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new int[]{1, 0},
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new int[]{-1, 0},
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new int[]{0, 1},
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new int[]{0, -1}
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);
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public void wallsAndGates(int[][] rooms) {
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int m = rooms.length;
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if (m == 0) {
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return;
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}
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int n = rooms[0].length;
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Queue<int[]> q = new LinkedList<>();
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for (int row = 0; row < m; row++) {
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for (int col = 0; col < n; col++) {
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if (rooms[row][col] == GATE) {
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q.add(new int[]{row, col});
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}
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}
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}
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while (!q.isEmpty()) {
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int[] point = q.poll();
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int row = point[0];
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int col = point[1];
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for (int[] direction : DIRECTIONS) {
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int r = row + direction[0];
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int c = col + direction[1];
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if (r < 0 || c < 0 || r >= m || c >= n || rooms[r][c] != EMPTY) {
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continue;
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}
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rooms[r][c] = rooms[row][col] + 1;
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q.add(new int[]{r, c});
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}
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}
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}
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}
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}
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