From a12dac92bf46c8d20b64ec794846a85babdf0ff9 Mon Sep 17 00:00:00 2001
From: Powfu <1875065753@qq.com>
Date: Wed, 27 Dec 2023 10:57:20 +0000
Subject: [PATCH] =?UTF-8?q?add=202101040022/chapter=5F8/=E8=AF=BE=E7=A8=8B?=
 =?UTF-8?q?=E8=A1=A8.cpp.?=
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Content-Transfer-Encoding: 8bit

Signed-off-by: Powfu <1875065753@qq.com>
---
 .../\350\257\276\347\250\213\350\241\250.cpp" | 50 +++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 "2101040022/chapter_8/\350\257\276\347\250\213\350\241\250.cpp"

diff --git "a/2101040022/chapter_8/\350\257\276\347\250\213\350\241\250.cpp" "b/2101040022/chapter_8/\350\257\276\347\250\213\350\241\250.cpp"
new file mode 100644
index 00000000..63167e3a
--- /dev/null
+++ "b/2101040022/chapter_8/\350\257\276\347\250\213\350\241\250.cpp"
@@ -0,0 +1,50 @@
+int** edges;
+int* edgeColSize;
+int* visited;
+bool valid;
+
+void dfs(int u) {
+    visited[u] = 1;
+    for (int i = 0; i < edgeColSize[u]; ++i) {
+        if (visited[edges[u][i]] == 0) {
+            dfs(edges[u][i]);
+            if (!valid) {
+                return;
+            }
+        } else if (visited[edges[u][i]] == 1) {
+            valid = false;
+            return;
+        }
+    }
+    visited[u] = 2;
+}
+
+bool canFinish(int numCourses, int** prerequisites, int prerequisitesSize, int* prerequisitesColSize) {
+    valid = true;
+    edges = (int**)malloc(sizeof(int*) * numCourses);
+    for (int i = 0; i < numCourses; i++) {
+        edges[i] = (int*)malloc(0);
+    }
+    edgeColSize = (int*)malloc(sizeof(int) * numCourses);
+    memset(edgeColSize, 0, sizeof(int) * numCourses);
+    visited = (int*)malloc(sizeof(int) * numCourses);
+    memset(visited, 0, sizeof(int) * numCourses);
+    for (int i = 0; i < prerequisitesSize; ++i) {
+        int a = prerequisites[i][1], b = prerequisites[i][0];
+        edgeColSize[a]++;
+        edges[a] = (int*)realloc(edges[a], sizeof(int) * edgeColSize[a]);
+        edges[a][edgeColSize[a] - 1] = b;
+    }
+    for (int i = 0; i < numCourses && valid; ++i) {
+        if (!visited[i]) {
+            dfs(i);
+        }
+    }
+    for (int i = 0; i < numCourses; i++) {
+        free(edges[i]);
+    }
+    free(edges);
+    free(edgeColSize);
+    free(visited);
+    return valid;
+}
\ No newline at end of file
-- 
Gitee