Runtime 411 ms (Top 60.7%) | Memory 90.0 MB (Top 81.41%)

Author: AnasImloul

scripts/algorithms/I/Insert Delete GetRandom O(1)/Insert Delete GetRandom O1.js

@@ -0,0 +1,68 @@
+var RandomizedSet = function() {
+    this._data = [];
+    this._flatData = [];
+};
+
+RandomizedSet.prototype.hash = function(val) {
+    return val % 1e5;
+}
+
+RandomizedSet.prototype.insert = function(val) {
+    const hash = this.hash(val);
+    let basket = this._data[hash];
+    
+    for (let i = 0; i < basket?.length; i++) {
+        if (basket[i][0] === val) { return false; }
+    }
+    
+    if (!basket) {
+        this._data[hash] = [[val, this._flatData.length]];
+    } else {
+        this._data[hash].push([val, this._flatData.length]);
+    }
+    this._flatData.push(val);    
+    return true;
+};
+
+RandomizedSet.prototype.remove = function(val) {
+    const hash = this.hash(val);
+    let basket = this._data[hash];
+    if (!basket) { return false; }
+    for (let i = 0; i < basket.length; i++) {
+        const currBasket = basket[i];
+        if (currBasket[0] === val) {
+            const idxInFlat = currBasket[1];
+            const reassignedValueInFlat = del(this._flatData, idxInFlat);
+            // Write new address in _data if needed
+            if (reassignedValueInFlat) {
+                this._data[this.hash(reassignedValueInFlat)].forEach(item => {
+                    if (item[0] === reassignedValueInFlat) {
+                        item[1] = idxInFlat;
+                        return; // from forEach
+                    }
+                });
+            }
+            // Delete from _data
+            del(basket, i);
+            return true;
+        }
+    }
+    return false;
+};
+
+RandomizedSet.prototype.getRandom = function() {
+    return this._flatData[getRandomInt(0, this._flatData.length - 1)];
+};
+
+function getRandomInt(min, max) {
+    min = Math.ceil(min);
+    max = Math.floor(max);
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+function del(arr, idx) {
+    if (!arr.length) { return null; }
+    if (idx === arr.length - 1) { arr.pop(); return null; }
+    arr[idx] = arr.pop();
+    return arr[idx];
+}