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| 6 | "use strict";
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| 7 |
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| 8 | const SAFE_LIMIT = 0x80000000;
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| 9 | const SAFE_PART = SAFE_LIMIT - 1;
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| 10 | const COUNT = 4;
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| 11 | const arr = [0, 0, 0, 0, 0];
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| 12 | const primes = [3, 7, 17, 19];
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| 13 |
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| 14 | module.exports = (str, range) => {
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| 15 | arr.fill(0);
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| 16 | for (let i = 0; i < str.length; i++) {
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| 17 | const c = str.charCodeAt(i);
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| 18 | for (let j = 0; j < COUNT; j++) {
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| 19 | const p = (j + COUNT - 1) % COUNT;
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| 20 | arr[j] = (arr[j] + c * primes[j] + arr[p]) & SAFE_PART;
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| 21 | }
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| 22 | for (let j = 0; j < COUNT; j++) {
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| 23 | const q = arr[j] % COUNT;
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| 24 | arr[j] = arr[j] ^ (arr[q] >> 1);
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| 25 | }
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| 26 | }
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| 27 | if (range <= SAFE_PART) {
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| 28 | let sum = 0;
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| 29 | for (let j = 0; j < COUNT; j++) {
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| 30 | sum = (sum + arr[j]) % range;
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| 31 | }
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| 32 | return sum;
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| 33 | } else {
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| 34 | let sum1 = 0;
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| 35 | let sum2 = 0;
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| 36 | const rangeExt = Math.floor(range / SAFE_LIMIT);
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| 37 | for (let j = 0; j < COUNT; j += 2) {
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| 38 | sum1 = (sum1 + arr[j]) & SAFE_PART;
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| 39 | }
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| 40 | for (let j = 1; j < COUNT; j += 2) {
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| 41 | sum2 = (sum2 + arr[j]) % rangeExt;
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| 42 | }
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| 43 | return (sum2 * SAFE_LIMIT + sum1) % range;
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| 44 | }
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| 45 | };
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