73 lines
1.9 KiB
JavaScript
73 lines
1.9 KiB
JavaScript
// TheSpanishInquisition
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// Cache the matrix. Note that if you not pass a limit this implementation will use a dynamically calculate one.
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module.exports = function(__this, that, limit) {
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var thisLength = __this.length,
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thatLength = that.length,
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matrix = [];
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// If the limit is not defined it will be calculate from this and that args.
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limit = (limit || ((thatLength > thisLength ? thatLength : thisLength)))+1;
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for (var i = 0; i < limit; i++) {
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matrix[i] = [i];
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matrix[i].length = limit;
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}
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for (i = 0; i < limit; i++) {
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matrix[0][i] = i;
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}
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if (Math.abs(thisLength - thatLength) > (limit || 100)){
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return prepare (limit || 100);
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}
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if (thisLength === 0){
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return prepare (thatLength);
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}
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if (thatLength === 0){
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return prepare (thisLength);
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}
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// Calculate matrix.
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var j, this_i, that_j, cost, min, t;
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for (i = 1; i <= thisLength; ++i) {
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this_i = __this[i-1];
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// Step 4
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for (j = 1; j <= thatLength; ++j) {
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// Check the jagged ld total so far
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if (i === j && matrix[i][j] > 4) return prepare (thisLength);
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that_j = that[j-1];
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cost = (this_i === that_j) ? 0 : 1; // Step 5
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// Calculate the minimum (much faster than Math.min(...)).
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min = matrix[i - 1][j ] + 1; // Deletion.
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if ((t = matrix[i ][j - 1] + 1 ) < min) min = t; // Insertion.
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if ((t = matrix[i - 1][j - 1] + cost) < min) min = t; // Substitution.
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// Update matrix.
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matrix[i][j] = (i > 1 && j > 1 && this_i === that[j-2] && __this[i-2] === that_j && (t = matrix[i-2][j-2]+cost) < min) ? t : min; // Transposition.
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}
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}
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return prepare (matrix[thisLength][thatLength]);
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/**
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*
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*/
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function prepare(steps) {
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var length = Math.max(thisLength, thatLength)
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var relative = length === 0
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? 0
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: (steps / length);
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var similarity = 1 - relative
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return {
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steps: steps,
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relative: relative,
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similarity: similarity
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};
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}
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};
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