最长公共序列LSC

 前面博客已经分析过了

just贴个代码

public class LongestCommonSubsequence
{public static void main(String[] args){//保留空字符串是为了getLength()方法的完整性也可以不保留//但是在getLength()方法里面必须额外的初始化c[][]第一个行第一列String[] x = {"", "x", "z", "y", "z", "z", "y", "x"};// String[] x = {"","M","A","E","E","E","V","A","K","L","E","K","H","L","M","L","L","R","Q","E","Y","V","K","L","Q","K","K","L","A","E","K","R","C","A","L","L","A","A","Q","A","N","K","E","S","S","S","E","S","F","I","S","R","L","L","A","I","V","A","D"};String[] y = {"", "z", "x", "y", "y", "z", "x","z"};//  String[] y = {"","M","A","E","E","E","V","A","K","L","E","K","H","L","M","L","L","R","Q","E","Y","V","K","K","L","A","E","T","E","K","R","C","T","L","L","A","A","Q","A","N","K","E","N","S","N","E","S","F","I","S","R","L","L","A","I","V","A","G"};int[][] b = getLength(x, y);Display(b, x, x.length-1, y.length-1);}public static int[][] getLength(String[] x, String[] y){int[][] b = new int[x.length][y.length];int[][] c = new int[x.length][y.length];for(int i=1; i<x.length; i++){for(int j=1; j<y.length; j++){if( x[i] == y[j]){c[i][j] = c[i-1][j-1] + 1;b[i][j] = 1;//标记斜向上箭头}else if(c[i-1][j] >= c[i][j-1]){c[i][j] = c[i-1][j];b[i][j] = 0;//标记向上箭头}//对应第二或者第三个性质else{c[i][j] = c[i][j-1];b[i][j] = -1;//标记向左箭头}}}return b;}//回溯的基本实现，采取递归的方式public static void Display(int[][] b, String[] x, int i, int j){if(i == 0 || j == 0)return;if(b[i][j] == 1){Display(b, x, i-1, j-1);//是斜向上箭头，打印路径System.out.print(x[i] + " ");}else if(b[i][j] == 0){Display(b, x, i-1, j);}else if(b[i][j] == -1){Display(b, x, i, j-1);}}
}

ps：打这一长串字母我真的园地趣事。。