java相似度算法计算

public class CompareStrSimUtil {
    private static int compare(String str, String target, boolean isIgnore) {
        int d[][]; // 矩阵
        int n = str.length();
        int m = target.length();
        int i; // 遍历str的
        int j; // 遍历target的
        char ch1; // str的
        char ch2; // target的
        int temp; // 记录相同字符,在某个矩阵位置值的增量,不是0就是1
        if (n == 0) {
            return m;
        }
        if (m == 0) {
            return n;
        }
        d = new int[n + 1][m + 1];
        for (i = 0; i <= n; i++) { // 初始化第一列
            d[i][0] = i;
        }

        for (j = 0; j <= m; j++) { // 初始化第一行
            d[0][j] = j;
        }

        for (i = 1; i <= n; i++) { // 遍历str
            ch1 = str.charAt(i - 1);
            // 去匹配target
            for (j = 1; j <= m; j++) {
                ch2 = target.charAt(j - 1);
                if (isIgnore) {
                    if (ch1 == ch2 || ch1 == ch2 + 32 || ch1 + 32 == ch2) {
                        temp = 0;
                    } else {
                        temp = 1;
                    }
                } else {
                    if (ch1 == ch2) {
                        temp = 0;
                    } else {
                        temp = 1;
                    }
                }

                // 左边+1,上边+1, 左上角+temp取最小
                d[i][j] = min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + temp);
            }
        }
        return d[n][m];
    }

    private static int min(int one, int two, int three) {
        return (one = one < two ? one : two) < three ? one : three;
    }

    public static float getSimilarityRatio(String str, String target, boolean isIgnore) {
        float ret = 0;
        if (Math.max(str.length(), target.length()) == 0) {
            ret = 1;
        } else {
            ret = 1 - (float) compare(str, target, isIgnore) / Math.max(str.length(), target.length());
        }
        return ret;
    }

    public static void main(String[] args) {
        CompareStrSimUtil lt = new CompareStrSimUtil();
        String str = "ab";
        String target = "ＡBC";
        System.out.println("similarityRatio=" + lt.getSimilarityRatio(str, target, true));
    }
}

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