From c88ede927478928962992409c5d70dc35070d3fa Mon Sep 17 00:00:00 2001
From: Kirito <1362050620@qq.com>
Date: Thu, 22 Sep 2022 08:55:42 +0800
Subject: [PATCH] Create 1640.cpp

---
 LeetCode/1640.cpp | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 LeetCode/1640.cpp

diff --git a/LeetCode/1640.cpp b/LeetCode/1640.cpp
new file mode 100644
index 0000000..91db197
--- /dev/null
+++ b/LeetCode/1640.cpp
@@ -0,0 +1,37 @@
+class Solution {
+public:
+    bool stepSearch(vector<int>& arr, vector<vector<int>>& pieces, vector<bool>& visited, int startIndex) {
+        for (int i = 0; i < pieces.size(); i++)
+        {
+            if (visited[i]) continue;
+            if (pieces[i][0] != arr[startIndex]) continue;
+            if (startIndex + pieces[i].size() > arr.size()) continue;
+
+            // check all elements
+            int j = 1;
+            for (; j < pieces[i].size(); j++) {
+                if (arr[startIndex + j] != pieces[i][j]) break;
+            }
+            if (j != pieces[i].size()) {
+                continue;
+            }
+
+            if (arr.size() == startIndex + pieces[i].size()) return true;
+
+            // step down
+            visited[i] = true;
+            bool ret = stepSearch(arr, pieces, visited, startIndex + pieces[i].size());
+            visited[i] = false;
+
+            if (ret) return true;
+        }
+
+        return false;
+    }
+
+    bool canFormArray(vector<int>& arr, vector<vector<int>>& pieces) {
+        vector<bool> visited(pieces.size(), false);
+
+        return stepSearch(arr, pieces, visited, 0);
+    }
+};