#few medium problems

Author: prabaprakash

count-triplets.js

@@ -0,0 +1,66 @@
+'use strict';
+
+const fs = require('fs');
+
+process.stdin.resume();
+process.stdin.setEncoding('utf-8');
+
+let inputString = '';
+let currentLine = 0;
+
+process.stdin.on('data', function (inputStdin) {
+    inputString += inputStdin;
+});
+
+process.stdin.on('end', function () {
+    inputString = inputString.split('\n');
+
+    main();
+});
+
+function readLine() {
+    return inputString[currentLine++];
+}
+function put(dict, key) {
+    dict[key] = dict[key] ? (dict[key] + 1) : 1;
+}
+// Complete the countTriplets function below.
+function countTriplets(arr, r) {
+    let a = {};
+    arr.forEach(x => {
+        put(a, x);
+    });
+    let b = {};
+    let s = 0;
+    console.log('a', a);
+    arr.forEach(i => {
+        let j = i / r;
+        let k = i * r;
+
+        a[i] = a[i] - 1;
+        if (b[j] && a[k]) {
+            console.log(j, i, k);
+            s += b[j] * a[k];
+        }
+        put(b, i);
+    });
+    return s;
+}
+
+function main() {
+    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);
+
+    const nr = readLine().replace(/\s+$/g, '').split(' ');
+
+    const n = parseInt(nr[0], 10);
+
+    const r = parseInt(nr[1], 10);
+
+    const arr = readLine().replace(/\s+$/g, '').split(' ').map(arrTemp => parseInt(arrTemp, 10));
+
+    const ans = countTriplets(arr, r);
+
+    ws.write(ans + '\n');
+
+    ws.end();
+}