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authorJack Sangdahl <[email protected]>2025-03-10 00:36:13 -0600
committerJack Sangdahl <[email protected]>2025-03-10 00:36:13 -0600
commit7c60dee83b436e8e8a667bf9f191beced8de4fc3 (patch)
treeeb7a24ee2067f92245c57bb118e85a1baf15df50 /other/modify_graph_edge_weight.cpp
parent5d7cdc215e4ba1ec4cbb24c084cccb5e5e641468 (diff)
downloadleetcode-7c60dee83b436e8e8a667bf9f191beced8de4fc3.tar.gz
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chore: move cpp and rust code to directory
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+// 2699. Modify Graph Edge Weights
+#include "leetcode.h"
+
+/*
+ * you are given an undirected weighted connected graph containing 'n' nodes
+ * labeled from '0' to 'n - 1' and an integer array 'edges' where 'edges[i] =
+ * [ai, bi, wi]' indicates that there is an edge between nodes 'ai' and 'bi'
+ * with weight 'wi'. some edges have a weight of -1 ('wi = -1'), while other
+ * have a positive weight ('wi > 0'). your task is to modify all edges with a
+ * weight of -1 by assigning them positive integer values in the range '[1, 2 *
+ * 10^9]' so that the shortest distance between the nodes 'source' and
+ * 'destination' becomes equal to an integer 'target'. if there are multiple
+ * modifications that make the shortest distance equal to 'target', any of them
+ * are considered correct. return an array containing all edges in any order if
+ * it is possible to make the shortest to equal 'target', or an empty array if
+ * it is not possible
+ */
+
+class Solution {
+ array<int, 2> bfs(vector<vector<array<int, 2>>> &adj,
+ vector<vector<int>> &edges, int source, int destination,
+ int target, bool modify) {
+ priority_queue<array<int, 2>, vector<array<int, 2>>, greater<>> pq;
+ vector<int> dist(adj.size(), INT_MAX), mod_id(adj.size(), INT_MAX);
+ pq.push({0, source});
+ dist[source] = 0;
+ while (!pq.empty() && pq.top()[1] != destination) {
+ auto [d, i] = pq.top();
+ pq.pop();
+ if (d != dist[i])
+ continue;
+ for (auto [j, edge_id] : adj[i]) {
+ int w = edges[edge_id][2];
+ if (modify || w != -1)
+ if (dist[j] > d + max(1, w)) {
+ mod_id[j] = w == -1 ? edge_id : mod_id[i];
+ dist[j] = d + max(1, w);
+ pq.push({d + max(1, w), j});
+ }
+ }
+ }
+ return {dist[destination], mod_id[destination]};
+ }
+
+public:
+ vector<vector<int>> modifiedGraphEdges(int n, vector<vector<int>> &edges,
+ int source, int destination,
+ int target) {
+ vector<vector<array<int, 2>>> adj(n);
+ for (int i = 0; i < edges.size(); ++i) {
+ adj[edges[i][0]].push_back({edges[i][1], i});
+ adj[edges[i][1]].push_back({edges[i][0], i});
+ }
+ auto [dist, _] = bfs(adj, edges, source, destination, target, false);
+ if (dist < target)
+ return {};
+ while (true) {
+ auto [dist, mod_id] = bfs(adj, edges, source, destination, target, true);
+ if (dist > target)
+ return {};
+ if (dist == target)
+ break;
+ edges[mod_id][2] = 1 + target - dist;
+ }
+ for (auto &e : edges)
+ e[2] = e[2] == -1 ? 1 : e[2];
+ return edges;
+ }
+};
+
+int main() {
+ Solution obj;
+ vvd e1 = {{4, 1, -1}, {2, 0, -1}, {0, 3, -1}, {4, 3, -1}},
+ e2 = {{0, 1, -1}, {0, 2, 5}},
+ e3 = {{1, 0, 4}, {1, 2, 3}, {2, 3, 5}, {0, 3, -1}};
+ vvd mge1 = obj.modifiedGraphEdges(5, e1, 0, 1, 5),
+ mge2 = obj.modifiedGraphEdges(3, e2, 0, 2, 6),
+ mge3 = obj.modifiedGraphEdges(4, e3, 0, 2, 6);
+ for (int i = 0; i < mge1.size(); i++)
+ for (int j = 0; j < mge1[0].size(); j++)
+ printf("%d ", mge1[i][j]); // expect: [[4,1,1],[2,0,1],[0,3,3],[4,3,1]]
+ printf("\n");
+ for (int i = 0; i < mge2.size(); i++)
+ for (int j = 0; j < mge2[0].size(); j++)
+ printf("%d ", mge2[i][j]); // expect: []
+ printf("\n");
+ for (int i = 0; i < mge3.size(); i++)
+ for (int j = 0; j < mge3[0].size(); j++)
+ printf("%d ", mge3[i][j]); // expect: [[1,0,4],[1,2,3],[2,3,5],[0,3,1]]
+ printf("\n");
+}