Merge pull request #2980 from rohankayan/main

Create: 0473-matchsticks-to-square.java

Author: felivalencia3

Diff for: java/0473-matchsticks-to-square.java

@@ -0,0 +1,40 @@
+class Solution {
+    boolean[] used;
+    public boolean makesquare(int[] matchsticks) {
+        used = new boolean[matchsticks.length];
+        int total = 0;
+        for (int n : matchsticks) {
+            total += n;
+        }
+        //Check if total of all the sides is divisible by 4 or not
+        if (total % 4 != 0) return false;
+        int side = total / 4;
+
+        return helper(matchsticks, side, 0, 0, 4);
+    }
+
+    boolean helper(int[] matchsticks, int targetSide, int currentSum, int index, int sides) {
+        //if all the sides are matching the target side length then we found a solution
+        if (sides == 0)
+            return true;
+        //Check if current side is equal to targetSide , that means we found another side
+        if (currentSum == targetSide) {
+            return helper(matchsticks, targetSide, 0, 0, sides - 1);
+        }
+
+        for (int i = index; i < matchsticks.length; i++) {
+            //Only use matchsticks which are not used and which doesn't increase the current side more than target side
+            if (!used[i] && currentSum + matchsticks[i] <= targetSide) {
+                used[i] = true;
+                boolean found = helper(matchsticks, targetSide, currentSum + matchsticks[i], i + 1, sides);
+                if (found) {
+                    return true;
+                }
+                used[i] = false;
+            }
+        }
+        return false;
+    }
+
+
+}