107 lines
2.7 KiB
Java
107 lines
2.7 KiB
Java
var isEqual = require('./is-segment-equal');
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function getMinDiff(del, add, modify) {
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var type = null;
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var min = modify;
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if (add < min) {
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min = add;
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type = 'add';
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}
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if (del < min) {
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min = del;
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type = 'del';
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}
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return {
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type: type,
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min: min
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};
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}
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/*
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* https://en.wikipedia.org/wiki/Levenshtein_distance
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* 计算两条path的编辑距离
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*/
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var levenshteinDistance = function levenshteinDistance(source, target) {
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var sourceLen = source.length;
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var targetLen = target.length;
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var sourceSegment = void 0,
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targetSegment = void 0;
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var temp = 0;
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if (sourceLen === 0 || targetLen === 0) {
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return null;
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}
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var dist = [];
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for (var i = 0; i <= sourceLen; i++) {
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dist[i] = [];
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dist[i][0] = { min: i };
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}
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for (var j = 0; j <= targetLen; j++) {
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dist[0][j] = { min: j };
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}
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for (var _i = 1; _i <= sourceLen; _i++) {
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sourceSegment = source[_i - 1];
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for (var _j = 1; _j <= targetLen; _j++) {
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targetSegment = target[_j - 1];
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if (isEqual(sourceSegment, targetSegment)) {
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temp = 0;
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} else {
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temp = 1;
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}
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var del = dist[_i - 1][_j].min + 1;
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var add = dist[_i][_j - 1].min + 1;
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var modify = dist[_i - 1][_j - 1].min + temp;
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dist[_i][_j] = getMinDiff(del, add, modify);
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}
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}
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return dist;
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};
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module.exports = function fillPathByDiff(source, target) {
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var diffMatrix = levenshteinDistance(source, target);
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var sourceLen = source.length;
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var targetLen = target.length;
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var changes = [];
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var index = 1;
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var minPos = 1;
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// 如果source和target不是完全不相等
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if (diffMatrix[sourceLen][targetLen] !== sourceLen) {
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// 获取从source到target所需改动
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for (var i = 1; i <= sourceLen; i++) {
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var min = diffMatrix[i][i].min;
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minPos = i;
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for (var j = index; j <= targetLen; j++) {
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if (diffMatrix[i][j].min < min) {
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min = diffMatrix[i][j].min;
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minPos = j;
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}
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}
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index = minPos;
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if (diffMatrix[i][index].type) {
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changes.push({ index: i - 1, type: diffMatrix[i][index].type });
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}
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}
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// 对source进行增删path
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for (var _i2 = changes.length - 1; _i2 >= 0; _i2--) {
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index = changes[_i2].index;
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if (changes[_i2].type === 'add') {
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source.splice(index, 0, [].concat(source[index]));
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} else {
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source.splice(index, 1);
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}
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}
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}
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// source尾部补齐
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sourceLen = source.length;
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if (sourceLen < targetLen) {
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for (var _i3 = 0; _i3 < targetLen - sourceLen; _i3++) {
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if (source[sourceLen - 1][0] === 'z' || source[sourceLen - 1][0] === 'Z') {
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source.splice(sourceLen - 2, 0, source[sourceLen - 2]);
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} else {
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source.push(source[sourceLen - 1]);
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}
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}
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}
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return source;
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}; |