/*
How to rank elements of an integer array based on their sorted order in JavaScript
---------------------------------------------------------------------------------
Ranking rules:
--------------
- Lowest value gets rank 1
- Equal values share the same rank
- Rank increases only when encountering a new unique value
Steps:
1. Print the original array
2. Create a copy of the array
3. Sort the copy
4. Build a map (value → rank)
5. Apply ranks back to the original order
*/
// ------------------------------------------------------------
// Function 1: Print the array
// ------------------------------------------------------------
function printArray(arr) {
console.log("Array:", arr);
}
// ------------------------------------------------------------
// Function 2: Create a copy of the array
// ------------------------------------------------------------
function copyArray(arr) {
return [...arr]; // spread operator copy
}
// ------------------------------------------------------------
// Function 3: Sort the array copy
// ------------------------------------------------------------
function sortArray(arrCopy) {
arrCopy.sort((a, b) => a - b); // ascending numeric sort
}
// ------------------------------------------------------------
// Function 4: Build a map of value → rank
// ------------------------------------------------------------
function buildRankMap(sortedArr) {
const map = new Map();
let rank = 1;
let previous = sortedArr[0];
map.set(previous, rank);
for (let i = 1; i < sortedArr.length; i++) {
if (sortedArr[i] !== previous) {
rank++;
}
map.set(sortedArr[i], rank);
previous = sortedArr[i];
}
return map;
}
// ------------------------------------------------------------
// Function 5: Apply ranks to original array order
// ------------------------------------------------------------
function applyRanks(original, map) {
const ranked = new Array(original.length);
for (let i = 0; i < original.length; i++) {
ranked[i] = map.get(original[i]);
}
return ranked;
}
// ------------------------------------------------------------
// Main ranking function
// ------------------------------------------------------------
function rankArray(arr) {
printArray(arr);
if (!arr || arr.length === 0)
return;
// Step 1: Copy array
const arrCopy = copyArray(arr);
// Step 2: Sort the copy
sortArray(arrCopy);
// Step 3: Build rank map
const rankMap = buildRankMap(arrCopy);
// Step 4: Apply ranks to original order
const ranked = applyRanks(arr, rankMap);
console.log("Rank:", ranked);
}
// ------------------------------------------------------------
// MAIN PROGRAM
// ------------------------------------------------------------
const arr = [33, 99, 10, 25, 47, 11, 77];
rankArray(arr);
/*
run:
Array: [
33, 99, 10, 25, 47, 11, 77
]
Rank: [
4, 7, 1, 3, 5, 2, 6
]
*/
