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| 1 | +class PossibleBipartitionKotlin886 { |
| 2 | + fun possibleBipartition(N: Int, dislikes: Array<IntArray>): Boolean { |
| 3 | + val dislikesMap: MutableMap<Int, MutableList<Int>> = HashMap() |
| 4 | + for (dislike in dislikes) { |
| 5 | + dislikesMap.computeIfAbsent(dislike[0]) { mutableListOf() }.add(dislike[1]) |
| 6 | + dislikesMap.computeIfAbsent(dislike[1]) { mutableListOf() }.add(dislike[0]) |
| 7 | + } |
| 8 | + val hashArray = IntArray(N + 1) |
| 9 | + for (index in hashArray.indices) { |
| 10 | + hashArray[index] = index |
| 11 | + } |
| 12 | + for (index in 1 until hashArray.size) { |
| 13 | + if (!dislikesMap[index].isNullOrEmpty()) { |
| 14 | + val currentHash = hash(hashArray, index) |
| 15 | + val dislikeList = dislikesMap.getValue(index) |
| 16 | + val first = hash(hashArray, dislikeList[0]) |
| 17 | + if (currentHash == first) { |
| 18 | + return false |
| 19 | + } |
| 20 | + for (d in 1 until dislikeList.size) { |
| 21 | + val dislikeHash = hash(hashArray, dislikeList[d]) |
| 22 | + if (currentHash == dislikeHash) { |
| 23 | + return false |
| 24 | + } |
| 25 | + hashArray[dislikeHash] = first |
| 26 | + } |
| 27 | + } |
| 28 | + } |
| 29 | + return true |
| 30 | + } |
| 31 | + |
| 32 | + private fun hash(hashArray: IntArray, target: Int): Int = when (target) { |
| 33 | + hashArray[target] -> target |
| 34 | + else -> hash(hashArray, hashArray[target]) |
| 35 | + } |
| 36 | + /* |
| 37 | + fun possibleBipartition(N: Int, dislikes: Array<IntArray>): Boolean { |
| 38 | + val dislikesMap: MutableMap<Int, MutableList<Int>> = HashMap() |
| 39 | + for (dislike in dislikes) { |
| 40 | + dislikesMap.computeIfAbsent(dislike[0]) { mutableListOf() }.add(dislike[1]) |
| 41 | + dislikesMap.computeIfAbsent(dislike[1]) { mutableListOf() }.add(dislike[0]) |
| 42 | + } |
| 43 | + val nArray = IntArray(N + 1) |
| 44 | + for (index in 1 until nArray.size) { |
| 45 | + if (nArray[index] == 0) { |
| 46 | + val queue: Queue<Int> = LinkedList() |
| 47 | + nArray[index] = 1 |
| 48 | + queue.offer(index) |
| 49 | + while (queue.isNotEmpty()) { |
| 50 | + val current = queue.poll() |
| 51 | + dislikesMap[current]?.forEach { |
| 52 | + when { |
| 53 | + nArray[it] == nArray[current] -> return false |
| 54 | + nArray[it] == 0 -> { |
| 55 | + nArray[it] = -nArray[current] |
| 56 | + queue.offer(it) |
| 57 | + } |
| 58 | + } |
| 59 | + } |
| 60 | + } |
| 61 | + } |
| 62 | + } |
| 63 | + return true |
| 64 | + } |
| 65 | + */ |
| 66 | + /* |
| 67 | + fun possibleBipartition(N: Int, dislikes: Array<IntArray>): Boolean { |
| 68 | + val dpDislikes = Array(N + 1) { IntArray(N + 1) } |
| 69 | + for (dislike in dislikes) { |
| 70 | + dpDislikes[dislike[0]][dislike[1]] = 1 |
| 71 | + dpDislikes[dislike[1]][dislike[0]] = 1 |
| 72 | + } |
| 73 | + val nArray = IntArray(N + 1) |
| 74 | + for (index in 1 until nArray.size) { |
| 75 | + if (nArray[index] == 0 && canNotGroup(index, 1, nArray, dpDislikes)) { |
| 76 | + return false |
| 77 | + } |
| 78 | + } |
| 79 | + return true |
| 80 | + } |
| 81 | +
|
| 82 | + private fun canNotGroup( |
| 83 | + n: Int, |
| 84 | + group: Int, |
| 85 | + nArray: IntArray, |
| 86 | + dpDislikes: Array<IntArray> |
| 87 | + ): Boolean = !canGroup(n, group, nArray, dpDislikes) |
| 88 | +
|
| 89 | + private fun canGroup( |
| 90 | + n: Int, |
| 91 | + group: Int, |
| 92 | + nArray: IntArray, |
| 93 | + dpDislikes: Array<IntArray> |
| 94 | + ): Boolean { |
| 95 | + nArray[n] = group |
| 96 | + for (index in 1 until dpDislikes.size) { |
| 97 | + if (dpDislikes[n][index] == 1) { |
| 98 | + when { |
| 99 | + nArray[index] == group -> return false |
| 100 | + nArray[index] == 0 && canNotGroup(index, -group, nArray, dpDislikes) -> return false |
| 101 | + } |
| 102 | + } |
| 103 | + } |
| 104 | + return true |
| 105 | + } |
| 106 | + */ |
| 107 | +} |
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