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+// 847. Shortest Path Visiting All Nodes
+#include "leetcode.h"
+
+/*
+ * you have an undirected, connected graph of 'n' nodes labeled from 0 to 'n -
+ * 1'. you are given an array 'graph' where 'graph[i]' is a list of all the
+ * nodes connected with node 'i' by an edge. return the length of the shortest
+ * path that visits every node. you may start and stop any any node. you may
+ * revisit nodes multiple times and you may reused edges.
+ */
+
+class Solution {
+public:
+ class tuple {
+ public:
+ int node;
+ int mask;
+ int cost;
+ tuple(int node, int mask, int cost) {
+ this->node = node;
+ this->mask = mask;
+ this->cost = cost;
+ }
+ };
+
+ int shortestPathLength(vvd & graph) {
+ int n = graph.size();
+ queue<tuple> q;
+ set<pair<int, int>> vis;
+ int all = (1 << n) - 1;
+ for (int i = 0; i < n; i++) {
+ int mask_val = 1 << i;
+ tuple curr(i, mask_val, 1);
+ q.push(curr);
+ vis.insert({i, mask_val});
+ }
+ while (!q.empty()) {
+ tuple curr = q.front();
+ q.pop();
+ if (curr.mask == all)
+ return curr.cost - 1;
+ for (auto adj : graph[curr.node]) {
+ int both_vis = curr.mask;
+ both_vis = both_vis | (1 << adj);
+ tuple node(adj, both_vis, curr.cost + 1);
+ if (vis.find({adj, both_vis}) == vis.end()) {
+ vis.insert({adj, both_vis});
+ q.push(node);
+ }
+ }
+ }
+ return -1;
+ }
+};
+
+int main() {
+ Solution obj;
+ vvd g1 = {{1, 2, 3}, {0}, {0}},
+ g2 = {{1}, {0, 2, 4}, {1, 3, 4}, {2}, {1, 2}};
+ printf("%d\n", obj.shortestPathLength(g1)); // expect: 4
+ printf("%d\n", obj.shortestPathLength(g2)); // expect: 4
+}