LCS最长公共子序列

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LCS最长公共子序列

            邝倍靖

最长公共子序列：已知两个字符串序列x、y，求他们的最长公共子序列，去表最长公共子串--连续的。

<img src="http://img.blog.csdn.net/20161024101358883?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

具体代码实现时，使用数据结构：二维数组c[m,n]，该数组表述

<img src="http://img.blog.csdn.net/20161024101909464?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

代码如下public class LCS {public static void main(String[] args) {//String str1 = "TCGGATCGACTT";//String str2 = "AGCCTACGTA";String str1 = "BCDABAB";String str2 = "CBACBAABA";int length = getMaxLength(str1, str2);}public static int getMaxLength(String str1,String str2){char[] s1 = str1.toCharArray();char[] s2 = str2.toCharArray();int size1 = str1.length();int size2 = str2.length();int[][] chess = new int[size1+1][size2+1];int i,j;for(i = 0; i<=size1; i++){chess[i][0] = 0;}for(j = 0; j<=size2; j++){chess[0][j] = 0;}for(i = 1; i<=size1; i++){for(j = 1; j<=size2; j++){if(s1[i-1] == s2[j-1]){chess[i][j] = chess[i-1][j-1] + 1;}else{chess[i][j] = Math.max(chess[i-1][j], chess[i][j-1]);}}}i = size1;j = size2;StringBuffer sb = new StringBuffer();while(i!=0 && j!=0){if(s1[i - 1] == s2[j - 1]){sb.append(s1[i-1]);i--;j--;}else{if(chess[i][j-1] > chess[i-1][j]){j--;}else {i--;}}}String result = reverse(sb.toString());System.out.println(result);return chess[size1][size2];}public static String reverse(String str){char[] charArray = str.toCharArray();char temp;int length = charArray.length;for(int i = 0; i<length/2; i++){temp = charArray[i];charArray[i] = charArray[length - i - 1];charArray[length - i - 1] = temp;}String s = String.copyValueOf(charArray);return s;}}

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