“This is the 10th day of my participation in the Gwen Challenge in November. Check out the details: The Last Gwen Challenge in 2021.”

takeaway

Fat friends in order to better help new students adapt to the algorithm and questions, recently we began a special assault step by step. We’re going to start with one of the most frustrating types of algorithms, dynamic programming and we’re going to do a 21-day incubation program. What are you waiting for? Come and join us for 21 days of dynamic programming challenge!!

21 Days Dynamic Planning Introduction

Given a non-negative integer numRows, generate the former numRows of the “Yang Hui triangle”.

In Yang Hui’s triangle, each number is the sum of the numbers on its upper left and upper right.

The sample1: Enter: numRows =5Output: [[1], [1.1], [1.2.1], [1.3.3.1], [1.4.6.4.1]]
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The sample2: Enter: numRows =1Output: [[1]]
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class Solution {
    public List<List<Integer>> generate(int numRows) {
        List<List<Integer>> ret = new ArrayList<List<Integer>>();
        for (int i = 0; i < numRows; ++i) {
            List<Integer> row = new ArrayList<Integer>();
            for (int j = 0; j <= i; ++j) {
                if (j == 0 || j == i) {
                    row.add(1);
                } else {
                    row.add(ret.get(i - 1).get(j - 1) + ret.get(i - 1).get(j));
                }
            }
            ret.add(row);
        }
        returnret; }}Copy the code

Given a non-negative index rowIndex, return the rowIndex row of the “Yang Hui triangle”.

In Yang Hui’s triangle, each number is the sum of the numbers on its upper left and upper right.

The sample1: Enter rowIndex =3Output:1.3.3.1]
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The sample2: Enter rowIndex =0Output:1]
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The sample3: Enter rowIndex =1Output:1.1]
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class Solution {
    public List<Integer> getRow(int rowIndex) {
        List<Integer> row = new ArrayList<Integer>();
        row.add(1);
        for (int i = 1; i <= rowIndex; ++i) {
            row.add(0);
            for (int j = i; j > 0; --j) {
                row.set(j, row.get(j) + row.get(j - 1)); }}returnrow; }}Copy the code

The interview questions

Continue with the previous Linux interview questions

19Kill command (used to send a signal to either a job (%jobnumber) or a PID (number), usually used with ps and jobs commands)20Killall command (sends a signal to a process started by a command)21The top command is a commonly used performance analysis tool in Linux. It displays the resource usage of each process in the system in real time, similar to the Task manager in Windows. How to kill a process: GUI mode kill -9Pid (-9Killall - Indicates mandatory shutdown9Program name Pkill Program nameCopy the code