(int n,int[][] edges,int source,int destination,int target)
| 4 | int INF = (int)1e9; |
| 5 | |
| 6 | public int[][] modifiedGraphEdges(int n,int[][] edges,int source,int destination,int target) { |
| 7 | //form the adjlist |
| 8 | // init |
| 9 | graph = new ArrayList[n]; |
| 10 | for (int i = 0; i < n; i++) { |
| 11 | graph[i] = new ArrayList<>(); |
| 12 | } |
| 13 | // exclude node with -1 value; |
| 14 | for (int[] edge : edges) { |
| 15 | if (edge[2] != -1) { |
| 16 | graph[edge[0]].add(new int[] { edge[1], edge[2] }); |
| 17 | graph[edge[1]].add(new int[] { edge[0], edge[2] }); |
| 18 | } |
| 19 | } |
| 20 | int minDist = runDijkstra(n, source, destination); |
| 21 | //not possible to meet target |
| 22 | if (minDist < target) { |
| 23 | return new int[0][0]; |
| 24 | } |
| 25 | // we don't need -1 weighted edges |
| 26 | if (minDist == target) { |
| 27 | for (int[] edge : edges) { |
| 28 | if(edge[2] == -1){ |
| 29 | edge[2] = INF; |
| 30 | } |
| 31 | } |
| 32 | return edges; |
| 33 | } |
| 34 | // if minDist > target (we can further reduce the minDist) |
| 35 | boolean matchesTarget = false; |
| 36 | for (int[] edge : edges) { |
| 37 | if (edge[2] != -1) continue; |
| 38 | edge[2] = matchesTarget ? INF : 1; |
| 39 | graph[edge[0]].add(new int[] { edge[1], edge[2] }); |
| 40 | graph[edge[1]].add(new int[] { edge[0], edge[2] }); |
| 41 | if (!matchesTarget) { |
| 42 | int newDistance = runDijkstra(n, source, destination); |
| 43 | if (newDistance <= target) { |
| 44 | matchesTarget = true; |
| 45 | edge[2] += target - newDistance; |
| 46 | } |
| 47 | } |
| 48 | } |
| 49 | return matchesTarget ? edges : new int[0][0]; |
| 50 | } |
| 51 | |
| 52 | // Dijkstra's algorithm to find the shortest path from source to destination |
| 53 | private int runDijkstra(int n, int source, int destination) { |
nothing calls this directly
no test coverage detected