hierarchical-estimates-visu.../packages/webpage-refactor/components/progressIndicator.js

49 lines
1.4 KiB
JavaScript

import React, { useState } from "react";
function expectedNumMergeSortSteps(n) {
// https://cs.stackexchange.com/questions/82862/expected-number-of-comparisons-in-a-merge-step
// n-2 for each step, so (n-2) + (n-2)/2 + (n-2)/4 + ...
// ~ 2*(n-2) -1 = 2*n - 3
if (n == 0) {
return 0;
} else if (n == 1) {
return 0;
} else if (n == 2) {
return 1;
} else if (n == 3) {
return 2;
} else {
return (
Math.ceil(n ** 2 / (n + 2)) + expectedNumMergeSortSteps(Math.ceil(n / 2))
);
}
}
const firstFewMaxMergeSortSequence = [
0, 0, 1, 3, 5, 8, 11, 14, 17, 21, 25, 29, 33, 37, 41, 45, 49, 54, 59, 64, 69,
74, 79, 84, 89, 94, 99, 104, 109, 114, 119, 124, 129, 135, 141, 147, 153, 159,
165, 171, 177, 183, 189, 195, 201, 207, 213, 219, 225, 231, 237, 243, 249,
255, 261, 267, 273, 279, 285,
];
function maxMergeSortSteps(n) {
if (n < firstFewMaxMergeSortSequence.length) {
return firstFewMaxMergeSortSequence[n];
} else {
return (
maxMergeSortSteps(Math.floor(n / 2)) +
maxMergeSortSteps(Math.ceil(n / 2)) +
n -
1
);
}
}
export function ProgressIndicator({ numStepsNow, numElements }) {
const expectedNumSteps = expectedNumMergeSortSteps(numElements);
const maxSteps = maxMergeSortSteps(numElements);
return (
<p>{`${numStepsNow} out of ~${expectedNumSteps} (max ${maxSteps}) comparisons`}</p>
);
}