1. 题目

读题

 HJ65 查找两个字符串a,b中的最长公共子串

考查点

2. 解法

思路

代码逻辑

具体实现

自行实现 

public class HJ065 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.println(dp(sc.nextLine(), sc.nextLine()));
    }

    public static String dp(String str1, String str2) {

        if (str1.length() > str2.length()) {
            String temp = str1;
            str1 = str2;
            str2 = temp;
        }
        int m = str1.length();
        int n = str2.length();
        int[][] dp = new int[m][n];

        int maxLen = 0;
        int index = 0;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (i == 0 && j == 0) {
                    dp[i][j] = str1.charAt(0) == str2.charAt(0) ? 1 : 0;
                } else if (i == 0) {
                    dp[i][j] = str1.charAt(0) == str2.charAt(j) ? 1 : 0;
                } else if (j == 0) {
                    dp[i][j] = str1.charAt(i) == str2.charAt(0) ? 1 : 0;
                } else {
                    if (str1.charAt(i) == str2.charAt(j)) {
                        dp[i][j] = dp[i - 1][j - 1] + 1;
                    } else {
                        dp[i][j] = 0;
                    }
                }

                if (dp[i][j] > maxLen) {
                    maxLen = dp[i][j];
                    index = i;
                }
            }

        }
        return str1.substring(index - maxLen + 1, index + 1);

    }
}

3. 总结