edit-distance/myers-1986

import assert from 'assert';

import longestCommonSuffix from './longestCommonSuffix.js';
/**
 * Diagonal backward extension subroutine.
 *
 * @param {number} cMin
 * @param {number} cMax
 * @param {number} cx
 * @param {{[x: number]: number}} V
 * @param {Function} eq
 * @param {number} lj
 * @param {number} rj
 */
export default function backwardExtend(
    cMin,
    cMax,
    cx,
    V,
    eq,
    // Li,
    lj,
    // Ri,
    rj,
) {
    for (let c = cMin; c <= cMax; c = (c + 2) | 0) {
        const x = V[c];
        const y = x - (c - cx);
        assert(x === lj - 2 || x === lj - 1 || x >= lj); // These should be true
        assert(y === rj - 2 || y === rj - 1 || y >= rj); // Provided you called
        // assert(x <= li); // BackwardStep(center, D, ...)
        // assert(y <= ri); // Just before.
        V[c] = longestCommonSuffix(eq, V[c], lj, (V[c] - ((c - cx) | 0)) | 0, rj);
    }
}