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| 1 | +/* |
| 2 | + * @lc app=leetcode.cn id=752 lang=java |
| 3 | + * |
| 4 | + * [752] 打开转盘锁 |
| 5 | + * |
| 6 | + * https://leetcode-cn.com/problems/open-the-lock/description/ |
| 7 | + * |
| 8 | + * algorithms |
| 9 | + * Medium (49.26%) |
| 10 | + * Likes: 118 |
| 11 | + * Dislikes: 0 |
| 12 | + * Total Accepted: 16.7K |
| 13 | + * Total Submissions: 34.2K |
| 14 | + * Testcase Example: '["0201","0101","0102","1212","2002"]\n"0202"' |
| 15 | + * |
| 16 | + * 你有一个带有四个圆形拨轮的转盘锁。每个拨轮都有10个数字: '0', '1', '2', '3', '4', '5', '6', '7', '8', |
| 17 | + * '9' 。每个拨轮可以自由旋转:例如把 '9' 变为 '0','0' 变为 '9' 。每次旋转都只能旋转一个拨轮的一位数字。 |
| 18 | + * |
| 19 | + * 锁的初始数字为 '0000' ,一个代表四个拨轮的数字的字符串。 |
| 20 | + * |
| 21 | + * 列表 deadends 包含了一组死亡数字,一旦拨轮的数字和列表里的任何一个元素相同,这个锁将会被永久锁定,无法再被旋转。 |
| 22 | + * |
| 23 | + * 字符串 target 代表可以解锁的数字,你需要给出最小的旋转次数,如果无论如何不能解锁,返回 -1。 |
| 24 | + * |
| 25 | + * |
| 26 | + * |
| 27 | + * 示例 1: |
| 28 | + * |
| 29 | + * |
| 30 | + * 输入:deadends = ["0201","0101","0102","1212","2002"], target = "0202" |
| 31 | + * 输出:6 |
| 32 | + * 解释: |
| 33 | + * 可能的移动序列为 "0000" -> "1000" -> "1100" -> "1200" -> "1201" -> "1202" -> "0202"。 |
| 34 | + * 注意 "0000" -> "0001" -> "0002" -> "0102" -> "0202" 这样的序列是不能解锁的, |
| 35 | + * 因为当拨动到 "0102" 时这个锁就会被锁定。 |
| 36 | + * |
| 37 | + * |
| 38 | + * 示例 2: |
| 39 | + * |
| 40 | + * |
| 41 | + * 输入: deadends = ["8888"], target = "0009" |
| 42 | + * 输出:1 |
| 43 | + * 解释: |
| 44 | + * 把最后一位反向旋转一次即可 "0000" -> "0009"。 |
| 45 | + * |
| 46 | + * |
| 47 | + * 示例 3: |
| 48 | + * |
| 49 | + * |
| 50 | + * 输入: deadends = ["8887","8889","8878","8898","8788","8988","7888","9888"], |
| 51 | + * target = "8888" |
| 52 | + * 输出:-1 |
| 53 | + * 解释: |
| 54 | + * 无法旋转到目标数字且不被锁定。 |
| 55 | + * |
| 56 | + * |
| 57 | + * 示例 4: |
| 58 | + * |
| 59 | + * |
| 60 | + * 输入: deadends = ["0000"], target = "8888" |
| 61 | + * 输出:-1 |
| 62 | + * |
| 63 | + * |
| 64 | + * |
| 65 | + * |
| 66 | + * 提示: |
| 67 | + * |
| 68 | + * |
| 69 | + * 死亡列表 deadends 的长度范围为 [1, 500]。 |
| 70 | + * 目标数字 target 不会在 deadends 之中。 |
| 71 | + * 每个 deadends 和 target 中的字符串的数字会在 10,000 个可能的情况 '0000' 到 '9999' 中产生。 |
| 72 | + * |
| 73 | + * |
| 74 | + */ |
| 75 | + |
| 76 | +// @lc code=start |
| 77 | +class Solution { |
| 78 | + public int openLock(String[] deadends, String target) { |
| 79 | + Set<String> deads = new HashSet<>(); |
| 80 | + for (String deadend : deadends) { |
| 81 | + deads.add(deadend); |
| 82 | + } |
| 83 | + |
| 84 | + Queue<String> queue = new LinkedList<>(); |
| 85 | + Set<String> visited = new HashSet<>(); |
| 86 | + queue.offer("0000"); |
| 87 | + visited.add("0000"); |
| 88 | + |
| 89 | + int step = 0; |
| 90 | + |
| 91 | + while (!queue.isEmpty()) { |
| 92 | + int size = queue.size(); |
| 93 | + |
| 94 | + for (int i = 0; i < size; i++) { |
| 95 | + String cur = queue.poll(); |
| 96 | + |
| 97 | + if (deads.contains(cur)) { |
| 98 | + continue; |
| 99 | + } |
| 100 | + if (cur.equals(target)) { |
| 101 | + return step; |
| 102 | + } |
| 103 | + |
| 104 | + for (int j = 0; j < 4; j++) { |
| 105 | + String plus = plusOne(cur, j); |
| 106 | + if (!visited.contains(plus)) { |
| 107 | + queue.offer(plus); |
| 108 | + visited.add(plus); |
| 109 | + } |
| 110 | + String minus = minusOne(cur, j); |
| 111 | + if (!visited.contains(minus)) { |
| 112 | + queue.offer(minus); |
| 113 | + visited.add(minus); |
| 114 | + } |
| 115 | + } |
| 116 | + } |
| 117 | + |
| 118 | + step++; |
| 119 | + } |
| 120 | + |
| 121 | + return -1; |
| 122 | + } |
| 123 | + |
| 124 | + public String plusOne(String str, int i) { |
| 125 | + char[] strArray = str.toCharArray(); |
| 126 | + if (strArray[i] == '9') { |
| 127 | + strArray[i] = '0'; |
| 128 | + } else { |
| 129 | + strArray[i] += 1; |
| 130 | + } |
| 131 | + return new String(strArray); |
| 132 | + } |
| 133 | + |
| 134 | + public String minusOne(String str, int i) { |
| 135 | + char[] strArray = str.toCharArray(); |
| 136 | + if (strArray[i] == '0') { |
| 137 | + strArray[i] = '9'; |
| 138 | + } else { |
| 139 | + strArray[i] -= 1; |
| 140 | + } |
| 141 | + return new String(strArray); |
| 142 | + } |
| 143 | +} |
| 144 | +// @lc code=end |
| 145 | + |
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