getNalargest.js

Author: amit265

javascript/4_array-programs/getNlargest.js

@@ -0,0 +1,88 @@
+// 33. Get N Largest Elements from an Array
+
+// Brute Force Approach
+
+// Example: If we have n=3 then array largArr will be having a length equal to 3 then we will run for loop one by one to fill the element in the largArr.
+
+{
+  let largArr = new Array();
+  let arr = new Array(93, 17, 56, 91, 98, 33, 9, 38, 55, 78, 29, 81, 60);
+
+  function largest() {
+    largArr[0] = 0;
+    largArr[1] = 0;
+    largArr[2] = 0;
+
+    for (let i = 0; i < arr.length; i++) {
+      if (arr[i] > largArr[0]) {
+        largArr[0] = arr[i];
+      }
+    }
+
+    for (let i = 0; i < arr.length; i++) {
+      if (arr[i] > largArr[1] && arr[i] < largArr[0]) {
+        largArr[1] = arr[i];
+      }
+    }
+    for (let i = 0; i < arr.length; i++) {
+      if (arr[i] > largArr[2] && arr[i] < largArr[1]) {
+        largArr[2] = arr[i];
+      }
+    }
+    console.log(largArr[0]);
+    console.log(largArr[1]);
+
+    console.log(largArr[2]);
+  }
+  largest();
+}
+
+// Optimized Solution:
+
+{
+  let largArr = new Array();
+  let arr = new Array(93, 17, 56, 91, 98, 33, 9, 38, 55, 78, 29, 81, 60);
+
+  findLargest3();
+  function findLargest3() {
+    //   arr.sort((a, b) => a < b ? 1 : a > b ? -1 : 0);
+    arr.sort((a, b) => b - a);
+    console.log(arr[0]);
+    console.log(arr[1]);
+    console.log(arr[2]);
+
+    console.log(arr.slice(0, 3));
+  }
+}
+
+// Using Math.max and filter() method
+
+{
+  function getNLargestELementWithFilter(arr, n) {
+    const largestELements = [];
+    for (let i = 0; i < n; i++) {
+      const max = Math.max(...arr);
+      largestELements.push(max);
+      arr = arr.filter((num) => num !== max);
+    }
+    return largestELements;
+  }
+
+  const array = [1, 8, 3, 5, 9, 2];
+  console.log(getNLargestELementWithFilter(array, 4));
+}
+
+// Using Array.reduce
+
+{
+  const array = [10, 5, 20, 8, 15];
+  const n = 3;
+  const largestELements = array.reduce((acc, curr) => {
+    if (acc.length < n || curr > acc[acc.length - 1]) {
+      acc.push(curr);
+    }
+    return acc.sort((a, b) => b - a).slice(0, n);
+  }, []);
+
+  console.log("Largest Elements:", largestELements);
+}