Merge pull request neetcode-gh#485 from hnlCaseSensitive/patch-3

473-matchsticks to square

Author: Ahmad-A0

javascript/473-Matchsticks-To-Square.js

@@ -0,0 +1,47 @@
+function check(arr){
+    let temp = arr[0];
+    for(let i = 1; i < arr.length; i++){
+        if(arr[i] !== temp){
+            return false;
+        }
+    }
+    return true;
+}
+
+/**
+ * @param {number[]} matchsticks
+ * @return {boolean}
+ */
+var makesquare = function(matchsticks) {
+    let sides = new Array(4).fill(0), ans = false, size = 0;
+    
+    for(let i = 0; i < matchsticks.length; i++){
+        size += matchsticks[i];
+    }
+    let max_size = size / 4;
+    if((max_size - Math.floor(max_size)) !== 0)return false;
+    
+    matchsticks = matchsticks.sort((a,b)=>b-a);
+    
+    function backtrack(i){
+        if(ans)return;
+        if(i >= matchsticks.length){
+            if(check(sides)){
+                ans = true;
+            }
+            return;
+        }
+        for(let j = 0; j < 4; j++){
+            if(sides[j] + matchsticks[i] > max_size){
+                continue;
+            }
+            sides[j] += matchsticks[i];
+
+            backtrack(i + 1);
+            sides[j] -= matchsticks[i];
+        }
+    }
+    backtrack(0);
+    
+    return ans;
+};