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138 lines
3.6 KiB
138 lines
3.6 KiB
const peq = new Uint32Array(0x10000); |
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const myers_32 = (a, b) => { |
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const n = a.length; |
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const m = b.length; |
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const lst = 1 << (n - 1); |
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let pv = -1; |
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let mv = 0; |
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let sc = n; |
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let i = n; |
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while (i--) { |
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peq[a.charCodeAt(i)] |= 1 << i; |
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} |
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for (i = 0; i < m; i++) { |
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let eq = peq[b.charCodeAt(i)]; |
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const xv = eq | mv; |
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eq |= ((eq & pv) + pv) ^ pv; |
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mv |= ~(eq | pv); |
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pv &= eq; |
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if (mv & lst) { |
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sc++; |
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} |
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if (pv & lst) { |
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sc--; |
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} |
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mv = (mv << 1) | 1; |
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pv = (pv << 1) | ~(xv | mv); |
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mv &= xv; |
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} |
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i = n; |
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while (i--) { |
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peq[a.charCodeAt(i)] = 0; |
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} |
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return sc; |
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}; |
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const myers_x = (b, a) => { |
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const n = a.length; |
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const m = b.length; |
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const mhc = []; |
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const phc = []; |
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const hsize = Math.ceil(n / 32); |
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const vsize = Math.ceil(m / 32); |
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for (let i = 0; i < hsize; i++) { |
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phc[i] = -1; |
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mhc[i] = 0; |
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} |
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let j = 0; |
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for (; j < vsize - 1; j++) { |
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let mv = 0; |
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let pv = -1; |
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const start = j * 32; |
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const vlen = Math.min(32, m) + start; |
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for (let k = start; k < vlen; k++) { |
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peq[b.charCodeAt(k)] |= 1 << k; |
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} |
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for (let i = 0; i < n; i++) { |
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const eq = peq[a.charCodeAt(i)]; |
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const pb = (phc[(i / 32) | 0] >>> i) & 1; |
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const mb = (mhc[(i / 32) | 0] >>> i) & 1; |
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const xv = eq | mv; |
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const xh = ((((eq | mb) & pv) + pv) ^ pv) | eq | mb; |
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let ph = mv | ~(xh | pv); |
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let mh = pv & xh; |
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if ((ph >>> 31) ^ pb) { |
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phc[(i / 32) | 0] ^= 1 << i; |
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} |
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if ((mh >>> 31) ^ mb) { |
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mhc[(i / 32) | 0] ^= 1 << i; |
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} |
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ph = (ph << 1) | pb; |
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mh = (mh << 1) | mb; |
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pv = mh | ~(xv | ph); |
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mv = ph & xv; |
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} |
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for (let k = start; k < vlen; k++) { |
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peq[b.charCodeAt(k)] = 0; |
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} |
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} |
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let mv = 0; |
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let pv = -1; |
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const start = j * 32; |
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const vlen = Math.min(32, m - start) + start; |
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for (let k = start; k < vlen; k++) { |
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peq[b.charCodeAt(k)] |= 1 << k; |
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} |
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let score = m; |
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for (let i = 0; i < n; i++) { |
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const eq = peq[a.charCodeAt(i)]; |
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const pb = (phc[(i / 32) | 0] >>> i) & 1; |
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const mb = (mhc[(i / 32) | 0] >>> i) & 1; |
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const xv = eq | mv; |
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const xh = ((((eq | mb) & pv) + pv) ^ pv) | eq | mb; |
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let ph = mv | ~(xh | pv); |
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let mh = pv & xh; |
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score += (ph >>> (m - 1)) & 1; |
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score -= (mh >>> (m - 1)) & 1; |
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if ((ph >>> 31) ^ pb) { |
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phc[(i / 32) | 0] ^= 1 << i; |
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} |
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if ((mh >>> 31) ^ mb) { |
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mhc[(i / 32) | 0] ^= 1 << i; |
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} |
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ph = (ph << 1) | pb; |
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mh = (mh << 1) | mb; |
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pv = mh | ~(xv | ph); |
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mv = ph & xv; |
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} |
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for (let k = start; k < vlen; k++) { |
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peq[b.charCodeAt(k)] = 0; |
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} |
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return score; |
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}; |
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const distance = (a, b) => { |
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if (a.length < b.length) { |
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const tmp = b; |
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b = a; |
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a = tmp; |
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} |
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if (b.length === 0) { |
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return a.length; |
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} |
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if (a.length <= 32) { |
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return myers_32(a, b); |
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} |
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return myers_x(a, b); |
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}; |
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const closest = (str, arr) => { |
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let min_distance = Infinity; |
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let min_index = 0; |
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for (let i = 0; i < arr.length; i++) { |
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const dist = distance(str, arr[i]); |
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if (dist < min_distance) { |
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min_distance = dist; |
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min_index = i; |
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} |
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} |
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return arr[min_index]; |
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}; |
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export { closest, distance };
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