48 lines
2.8 KiB
JavaScript
48 lines
2.8 KiB
JavaScript
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function compareTwoStrings(first, second) {
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if ((first = first.replace(/\s+/g, '')) === (second = second.replace(/\s+/g, ''))) return 1;
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if (first.length < 2 || second.length < 2) return 0;
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var firstBigrams = new Map();
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for (let i = 0; i < first.length - 1; i++) {
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var bigram = first.substring(i, i + 2),
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count = firstBigrams.has(bigram) ? firstBigrams.get(bigram) + 1 : 1;
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firstBigrams.set(bigram, count);
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}
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let intersectionSize = 0;
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for (let i = 0; i < second.length - 1; i++) {
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const bigram = second.substring(i, i + 2),
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count = firstBigrams.has(bigram) ? firstBigrams.get(bigram) : 0;
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0 < count && (firstBigrams.set(bigram, count - 1), intersectionSize++);
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}
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return (2 * intersectionSize) / (first.length + second.length - 2);
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}
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function findBestMatch(mainString, targetStrings) {
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var ratings = [];
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let bestMatchIndex = 0;
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for (let i = 0; i < targetStrings.length; i++) {
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var currentTargetString = targetStrings[i],
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currentRating = compareTwoStrings(mainString, currentTargetString);
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ratings.push({ target: currentTargetString, rating: currentRating }), currentRating > ratings[bestMatchIndex].rating && (bestMatchIndex = i);
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}
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return { ratings: ratings, bestMatch: ratings[bestMatchIndex], bestMatchIndex: bestMatchIndex };
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}
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function lcs(str1, str2) {
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if (!str1 || !str2) return { length: 0, sequence: '', offset: 0 };
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for (var sequence = '', str1Length = str1.length, str2Length = str2.length, num = new Array(str1Length), maxlen = 0, lastSubsBegin = 0, i = 0; i < str1Length; i++) {
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for (var subArray = new Array(str2Length), j = 0; j < str2Length; j++) subArray[j] = 0;
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num[i] = subArray;
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}
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for (var thisSubsBegin = null, i = 0; i < str1Length; i++) for (j = 0; j < str2Length; j++) str1[i] !== str2[j] ? (num[i][j] = 0) : ((num[i][j] = 0 === i || 0 === j ? 1 : 1 + num[i - 1][j - 1]), num[i][j] > maxlen && ((maxlen = num[i][j]), lastSubsBegin === (thisSubsBegin = i - num[i][j] + 1) ? (sequence += str1[i]) : ((lastSubsBegin = thisSubsBegin), (sequence = ''), (sequence += str1.substr(lastSubsBegin, i + 1 - lastSubsBegin)))));
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return { length: maxlen, sequence: sequence, offset: thisSubsBegin };
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}
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function findBestLCS(mainString, targetStrings) {
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var results = [];
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let bestMatchIndex = 0;
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for (let i = 0; i < targetStrings.length; i++) {
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var currentTargetString = targetStrings[i],
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currentLCS = lcs(mainString, currentTargetString);
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results.push({ target: currentTargetString, lcs: currentLCS }), currentLCS.length > results[bestMatchIndex].lcs.length && (bestMatchIndex = i);
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}
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return { allLCS: results, bestMatch: results[bestMatchIndex], bestMatchIndex: bestMatchIndex };
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}
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export { compareTwoStrings, findBestMatch, findBestLCS };
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