62 lines
1.8 KiB
JavaScript
62 lines
1.8 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.csLeaf = csLeaf;
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// Copyright (c) 2006-2024, Timothy A. Davis, All Rights Reserved.
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// SPDX-License-Identifier: LGPL-2.1+
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// https://github.com/DrTimothyAldenDavis/SuiteSparse/tree/dev/CSparse/Source
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/**
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* This function determines if j is a leaf of the ith row subtree.
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* Consider A(i,j), node j in ith row subtree and return lca(jprev,j)
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*
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* @param {Number} i The ith row subtree
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* @param {Number} j The node to test
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* @param {Array} w The workspace array
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* @param {Number} first The index offset within the workspace for the first array
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* @param {Number} maxfirst The index offset within the workspace for the maxfirst array
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* @param {Number} prevleaf The index offset within the workspace for the prevleaf array
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* @param {Number} ancestor The index offset within the workspace for the ancestor array
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*
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* @return {Object}
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*/
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function csLeaf(i, j, w, first, maxfirst, prevleaf, ancestor) {
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let s, sparent;
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// our result
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let jleaf = 0;
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let q;
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// check j is a leaf
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if (i <= j || w[first + j] <= w[maxfirst + i]) {
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return -1;
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}
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// update max first[j] seen so far
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w[maxfirst + i] = w[first + j];
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// jprev = previous leaf of ith subtree
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const jprev = w[prevleaf + i];
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w[prevleaf + i] = j;
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// check j is first or subsequent leaf
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if (jprev === -1) {
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// 1st leaf, q = root of ith subtree
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jleaf = 1;
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q = i;
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} else {
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// update jleaf
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jleaf = 2;
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// q = least common ancester (jprev,j)
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for (q = jprev; q !== w[ancestor + q]; q = w[ancestor + q]);
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for (s = jprev; s !== q; s = sparent) {
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// path compression
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sparent = w[ancestor + s];
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w[ancestor + s] = q;
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}
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}
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return {
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jleaf,
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q
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};
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}
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