how to get sorted index of min values of 2d array

Question

having 2d number array like;

const arr = [
  [1, 5, 9],
  [2, 7, 8],
  [3, 0, 6],
];

what is the simplest way to get sorted array of array indexes where sort critera is values of original 2d array?

result should be:

  `[2,1]`, // (value=0)
  `[0,0]`, // (value=1)
  `[2,0]`, // (value=2)
  `[0,1]`, // (value=3)
  ...

btw, actual values are floats not that it matters.
but complexity does matter as loop runs on each frame.

Answer 1

Something like this?

const arr = [
  [1, 5, 9],
  [2, 7, 8],
  [3, 0, 6],
];

const map = []

arr.forEach((row, rowIndex) => row.forEach((col, colIndex) => {
  map.push({ c: colIndex, r: rowIndex, value: col });
}))

console.log(map)
const sorted = map.sort((a, b) => {
  if(a.value === b.value) return 0;
  return a.value > b.value ? 1 : -1;
})

console.log(sorted)
console.log(sorted.map(v => [v.r, v.c]))

it's working version, not optimalized

EDIT: little optimalization with execution time measure:

const arr = [
  [1, 5, 9],
  [2, 7, 8],
  [3, 0, 6],
];

const sortFn = (a, b) => a.value === b.value ? 0 : a.value > b.value ? 1 : -1;

let count = 3;
function process(arr) {
  const map = []
  arr.forEach((row, rowIndex) => row.forEach((col, colIndex) => {
    map.push({ row: rowIndex, col: colIndex, value: col });
  }))
  return map.sort(sortFn).map(v => [v.row, v.col]);
}

const interval = setInterval(() => {
  console.time("process");
  console.log(process(arr))
  console.timeEnd("process");
  if(--count === 0) clearInterval(interval);
}, 100)

Output:

[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 3.822ms
[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 1.661ms
[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 1.665ms

EDIT 2: (inspired by another answer with flatMap)

const arr = [
  [1, 5, 9],
  [2, 7, 8],
  [3, 0, 6],
];

const sortFn = (a, b) => a.value === b.value ? 0 : a.value > b.value ? 1 : -1;
arr.flatMap((_row, row) => _row.map((value, col) => { return { row, col, value } })).sort(sortFn).map(v => [v.row, v.col]);

let count = 3;
const process = (arr) => arr.flatMap((_row, row) => _row.map((value, col) => { return { row, col, value } })).sort(sortFn).map(v => [v.row, v.col]);

const interval = setInterval(() => {
  console.time("process");
  console.log(process(arr))
  console.timeEnd("process");
  if(--count === 0) clearInterval(interval);
}, 100)

Result:

[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 10.979ms
[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 1.346ms
[
  [ 2, 1 ], [ 0, 0 ],
  [ 1, 0 ], [ 2, 0 ],
  [ 0, 1 ], [ 2, 2 ],
  [ 1, 1 ], [ 1, 2 ],
  [ 0, 2 ]
]
process: 2.043ms