| /* |
| * Copyright 2000-2014 JetBrains s.r.o. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.intellij.util.diff; |
| |
| import gnu.trove.TIntIntHashMap; |
| |
| public class UniqueLCS { |
| private final int[] myFirst; |
| private final int[] mySecond; |
| |
| private final int myStart1; |
| private final int myStart2; |
| private final int myCount1; |
| private final int myCount2; |
| |
| public UniqueLCS(int[] first, int[] second) { |
| this(first, second, 0, first.length, 0, second.length); |
| } |
| |
| public UniqueLCS(int[] first, int[] second, int start1, int count1, int start2, int count2) { |
| myFirst = first; |
| mySecond = second; |
| myStart1 = start1; |
| myStart2 = start2; |
| myCount1 = count1; |
| myCount2 = count2; |
| } |
| |
| public int[][] execute() { |
| // map: key -> (offset1 + 1) |
| // match: offset1 -> (offset2 + 1) |
| TIntIntHashMap map = new TIntIntHashMap(myCount1 + myCount2); |
| int[] match = new int[myCount1]; |
| |
| for (int i = 0; i < myCount1; i++) { |
| int index = myStart1 + i; |
| int val = map.get(myFirst[index]); |
| |
| if (val == -1) continue; |
| if (val == 0) { |
| map.put(myFirst[index], i + 1); |
| } |
| else { |
| map.put(myFirst[index], -1); |
| } |
| } |
| |
| int count = 0; |
| for (int i = 0; i < myCount2; i++) { |
| int index = myStart2 + i; |
| int val = map.get(mySecond[index]); |
| |
| if (val == 0 || val == -1) continue; |
| if (match[val - 1] == 0) { |
| match[val - 1] = i + 1; |
| count++; |
| } |
| else { |
| match[val - 1] = 0; |
| map.put(mySecond[index], -1); |
| count--; |
| } |
| } |
| |
| if (count == 0) { |
| return null; |
| } |
| |
| // Largest increasing subsequence on unique elements |
| int[] sequence = new int[count]; |
| int[] lastElement = new int[count]; |
| int[] predecessor = new int[myCount1]; |
| |
| int length = 0; |
| for (int i = 0; i < myCount1; i++) { |
| if (match[i] == 0) continue; |
| |
| int j = binarySearch(sequence, match[i], length); |
| if (j == length || match[i] < sequence[j]) { |
| sequence[j] = match[i]; |
| lastElement[j] = i; |
| predecessor[i] = j > 0 ? lastElement[j - 1] : -1; |
| if (j == length) { |
| length++; |
| } |
| } |
| } |
| |
| int[][] ret = new int[][]{new int[length], new int[length]}; |
| |
| int i = length - 1; |
| int curr = lastElement[length - 1]; |
| while (curr != -1) { |
| ret[0][i] = curr; |
| ret[1][i] = match[curr] - 1; |
| i--; |
| curr = predecessor[curr]; |
| } |
| |
| return ret; |
| } |
| |
| // find max i: a[i] < val |
| // return i + 1 |
| // assert a[i] != val |
| private static int binarySearch(int[] sequence, int val, int length) { |
| int left = -1; |
| int right = length; |
| |
| while (right - left > 1) { |
| int middle = (left + right) / 2; |
| if (sequence[middle] > val) { |
| right = middle; |
| } |
| else { |
| left = middle; |
| } |
| } |
| return left + 1; |
| } |
| } |