POJ 1458 Common Subsequence 最长公共子序列（LCS）

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Scanner;

public class Main {

/**
* Q: 为什么这个数组每次使用都不需要清空？
* A: 因为数组最上边的一行全部为 0 && 最左边的一列也全部为 0 ，
*   而后续的值都是根据这一行一列来定值的。
*/
private static int[][] maxLen = new int[1000][1000];

private static int work(String str, String str2) {
char[] ch = str.toCharArray();
char[] ch2 = str2.toCharArray();
int length = ch.length;
int length2 = ch2.length;
for (int i = 1; i <= length; i++) {
for (int j = 1; j <= leng
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th2; j++) {
if (ch[i - 1] == ch2[j - 1]) {
maxLen[i][j] = maxLen[i - 1][j - 1] + 1;
} else {
maxLen[i][j] = Math.max(maxLen[i][j - 1], maxLen[i - 1][j]);
}
}
}
return maxLen[length][length2];
}

public static void main(String[] args) {
Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
String inputStr;
String inputStr2;
while (in.hasNext()) {
inputStr = in.next();
inputStr2 = in.next();
out.println(work(inputStr, inputStr2));
}
out.flush();
}
}