Create largest-color-value-in-a-directed-graph.cpp

Author: kamyu104

C++/largest-color-value-in-a-directed-graph.cpp

@@ -0,0 +1,39 @@
+// Time:  O(n + m)
+// Space: O(n + m)
+
+class Solution {
+public:
+    int largestPathValue(string colors, vector<vector<int>>& edges) {
+        vector<vector<int>> adj(size(colors));
+        vector<int> in_degree(size(colors));
+        for (const auto& edge : edges) {
+            adj[edge[0]].emplace_back(edge[1]);
+            ++in_degree[edge[1]];
+        }
+        vector<int> q;
+        for (int i = 0; i < size(colors); ++i) {
+            if (!in_degree[i]) {
+                q.emplace_back(i);
+            }
+        }
+        vector<vector<int>> dp(size(colors), vector<int>(26));
+        int result = -1, cnt = 0;
+        while (!empty(q)) {
+            vector<int> new_q;
+            for (const auto& u : q) {
+                ++cnt;
+                result = max(result, ++dp[u][colors[u] - 'a']);
+                for (const auto& v : adj[u]) {
+                    for (int c = 0; c < 26; ++c) {
+                        dp[v][c] = max(dp[v][c], dp[u][c]);
+                    }
+                    if (!--in_degree[v]) {
+                        new_q.emplace_back(v);
+                    }
+                }
+            }
+            q = move(new_q);
+        }
+        return cnt == size(colors) ? result : -1;
+    }
+};