Solution as on 12-07-2022 10:20 pm

Author: knockcat

0473. Matchsticks to Square.cpp

@@ -0,0 +1,46 @@
+// 473.✅ Matchsticks to Square
+
+class Solution
+{
+public:
+    bool helper(vector<int> &matchsticks, int target, vector<int> &sides, int idx)
+    {
+        if (idx == matchsticks.size())
+        {
+            if (sides[0] == sides[1] && sides[1] == sides[2] && sides[2] == sides[3])
+                return true;
+            return false;
+        }
+
+        for (int i = 0; i < 4; ++i)
+        {
+            if (sides[i] + matchsticks[idx] > target)
+                continue;
+            int j = i - 1;
+            while (j >= 0)
+            {
+                if (sides[i] == sides[j])
+                    break;
+                --j;
+            }
+            if (j != -1)
+                continue;
+            sides[i] += matchsticks[idx];
+            if (helper(matchsticks, target, sides, idx + 1))
+                return true;
+            sides[i] -= matchsticks[idx];
+        }
+        return false;
+    }
+
+    bool makesquare(vector<int> &matchsticks)
+    {
+        if (matchsticks.size() == 0)
+            return false;
+        int sum = 0;
+        sum = accumulate(matchsticks.begin(), matchsticks.end(), 0);
+        vector<int> sides(4, 0);
+        sort(matchsticks.begin(), matchsticks.end(), greater<int>());
+        return helper(matchsticks, sum / 4, sides, 0);
+    }
+};