Question

link

Output top N positive integer in string comparison order. For example, let’s say N=1000, then you need to output in string comparison order as below:

1, 10, 100, 1000, 101, 102, … 109, 11, 110, … 998, 999.

Solution

Thought for a while, and realize it’s stanard DFS.

Code

written by me

public static void main(String args[]) {
    for (int i = 1; i < 10; i++) {
        dfs("" + i);
    }
}

public static void dfs(String path) {
    if (Integer.parseInt(path) > 1000) {
        return;
    }
    System.out.println(path);
    for (int i = 0; i < 10; i++) {
        dfs(path + i);
    }
}