- 和为零的三元组
地址：MIOJ 15. 和为零的三元组
package lambdasinaction.playground.mioj;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* @author li2niu
* @date 2020/10/21
* @Description
*/
public class TriElementsEquals0 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String line;
while (scan.hasNextLine()) {
line = scan.nextLine().trim();
List<Integer> elements = Arrays.stream(line.split(",")).map(Integer::parseInt).collect(Collectors.toList());
int size = elements.size();
if (size < 3) {
System.out.println(0);
return;
}
Set<String> answerSetList = new HashSet<>();
getAnswer1(answerSetList, elements);
System.out.println(answerSetList.size());
Set<String> answerSetList2 = new HashSet<>();
getAnswer2(answerSetList2, elements);
System.out.println(answerSetList2.size());
}
}
/**
* 先确定中间的数字，然后两边的数字左右移动调节寻找符合条件的三元组
* O(n^2)
* @param answerSetList
* @param elements
*/
private static void getAnswer1(Set<String> answerSetList, List<Integer> elements) {
int maxIndex, minIndex;
List<Integer> sortedList = elements.parallelStream().sorted().collect(Collectors.toList());
int size = sortedList.size();
for (int i = 1; i < size - 1; i++) {
minIndex = i - 1;
maxIndex = i + 1;
while (minIndex >= 0 && maxIndex < size) {
int sum = sortedList.get(i) + sortedList.get(minIndex) + sortedList.get(maxIndex);
if (sum == 0) {
String result = sortedList.get(minIndex) + "," + sortedList.get(i) + "," + sortedList.get(maxIndex);
answerSetList.add(result);
minIndex--;
} else if (sum > 0) {
minIndex--;
} else {
maxIndex++;
}
}
}
}
/**
* 枚举所有的组合然后寻找符合条件的三元组
* O（n*(n-1)*(n-2)）=> O(n^3) (*☻-☻*)）
* @param answerSetList
* @param elements
*/
private static void getAnswer2(Set<String> answerSetList, List<Integer> elements) {
int size = elements.size();
for (int i = 0; i < size; i++) {
Integer element = elements.get(i);
Queue<Integer> queue = new LinkedList<>();
for (int j = 0; j < size; j++) {
if (j != i) {
queue.add(elements.get(j));
}
}
Integer pop1;
int poll1Count = 0;
while (poll1Count <= queue.size() && (pop1 = queue.poll()) != null) {
poll1Count++;
Integer pop2;
int poll2Count = 0;
while (poll2Count <= queue.size() - 1 && (pop2 = queue.poll()) != null) {
poll2Count++;
if (pop1 + pop2 + element == 0) {
String result = Stream.of(pop1, element, pop2)
.sorted()
.map(String::valueOf)
.collect(Collectors.joining(","));
answerSetList.add(result);
}
queue.add(pop2);
}
queue.add(pop1);
}
}
}
}
- 数独游戏
地址：MIOJ 45.数独游戏
leetcode Valid sudoku
这题有错误
leetcode版本
package playground.leetcode.sudoku;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
/**
* @author lichuanyi
* @date 2020/10/22
* @Description
*/
public class Solution {
private static final String case1 = "8,3,.,.,7,.,.,.,. 6,.,.,1,9,5,.,.,. .,9,8,.,.,.,.,6,. 8,.,.,.,6,.,.,.,3 4,.,.,8,.,3,.,.,1 7,.,.,.,2,.,.,.,6 .,6,.,.,.,.,2,8,. .,.,.,4,1,9,.,.,5 .,.,.,.,8,.,.,7,9";
private static final String case2 = "5,3,.,.,7,.,.,.,. 6,.,.,1,9,5,.,.,. .,9,8,.,.,.,.,6,. 8,.,.,.,6,.,.,.,3 4,.,.,8,.,3,.,.,1 7,.,.,.,2,.,.,.,6 .,6,.,.,.,.,2,8,. .,.,.,4,1,9,.,.,5 .,.,.,.,8,.,.,7,9";
private static final String case3 = ".,.,.,.,5,.,.,1,. .,4,.,3,.,.,.,.,. .,.,.,.,.,3,.,.,1 8,.,.,.,.,.,.,2,. .,.,2,.,7,.,.,.,. .,1,5,.,.,.,.,.,. .,.,.,.,.,2,.,.,. .,2,.,9,.,.,.,.,. .,.,4,.,.,.,.,.,.";
private static final String case4 = "5,3,.,.,7,.,.,.,. 6,.,.,1,9,5,.,.,. .,9,8,.,.,.,.,6,. 8,.,.,.,6,.,.,.,3 4,.,.,8,.,3,.,.,1 7,.,.,.,2,.,.,.,6 .,6,.,.,.,.,2,8,. .,.,.,4,1,9,.,.,5 .,.,.,.,8,.,.,7,9";
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String line;
while (scan.hasNextLine()) {
line = scan.nextLine().trim();
String[] sudokuLines = line.split(" ");
char[][] board = initBoard(sudokuLines);
printBoard(board);
System.out.println(new Solution().isValidSudoku(board));
}
}
private static void printBoard(char[][] board) {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
System.out.print(board[i][j]+" ");
}
System.out.println();
}
}
private static char[][] initBoard(String[] sudokuLines) {
char[][] board = new char[9][9];
for (int i = 0; i < 9; i++) {
String line = sudokuLines[i];
final String[] stones = line.split(",");
for (int j = 0; j < 9; j++) {
board[i][j] = ".".equals(stones[j]) ? '.' : stones[j].charAt(0);
}
}
return board;
}
public boolean isValidSudoku(char[][] board) {
Map<Character, Integer> map = new HashMap<>(9);
boolean result = validateRows(board, map);
if (!result) {
return false;
}
map.clear();
result = validateColumns(board, map);
if (!result) {
return false;
}
map.clear();
result = validate9Cells(board, map);
return result;
}
private boolean validateRows(char[][] board, Map<Character, Integer> map) {
for (int i = 0; i < 9; i++) {
map.clear();
for (int j = 0; j < 9; j++) {
if (map.containsKey(board[i][j])) {
return false;
}
if (board[i][j] != '.') {
map.put(board[i][j], 0);
}
}
}
return true;
}
/**
* 校验九个小方格
*
* @param board
* @param map
*/
private static boolean validate9Cells(char[][] board, Map<Character, Integer> map) {
for (int i = 0; i < 3; i++) {
for (int l = 0; l < 3; l++) {
map.clear();
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) {
char stone = board[i * 3 + j][3*l+k];
if (map.containsKey(stone)) {
return false;
}
if (stone != '.') {
map.put(stone, 0);
}
}
}
}
}
return true;
}
/**
* 校验列
*
* @param board
* @param map
*/
private static boolean validateColumns(char[][] board, Map<Character, Integer> map) {
for (int i = 0; i < 9; i++) {
map.clear();
for (int j = 0; j < 9; j++) {
char stone = board[j][i];
if (map.containsKey(stone)) {
return false;
}
if (stone != '.') {
map.put(stone, 0);
}
}
}
return true;
}
/**
* 初始化棋盘同时按行校验
*
* @param sudokuLines
* @param map
* @return
*/
private static int[][] initBoardAndValidateRows(String[] sudokuLines, Map<Integer, Integer> map) {
int[][] board = new int[9][9];
for (int i = 0; i < 9; i++) {
String line = sudokuLines[i];
final String[] stones = line.split(",");
map.clear();
for (int j = 0; j < 9; j++) {
board[i][j] = "-".equals(stones[j]) ? 0 : Integer.parseInt(stones[j]);
if (map.containsKey(board[i][j])) {
System.out.println(false);
return new int[0][];
}
if (board[i][j] != 0) {
map.put(board[i][j], 0);
}
}
}
return board;
}
}
mioj版本
package playground.mioj.day1.sudoku;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
/**
* @author: lichuanyi
* @description:
* @date: 2020/10/21 23:35
*/
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String line;
while (scan.hasNextLine()) {
line = scan.nextLine().trim();
String[] sudokuLines = line.split(" ");
Map<Integer,Integer> map = new HashMap<>(9);
int[][] board = initBoardAndValidateRows(sudokuLines,map);
if (board.length == 0){
return;
}
// else{
// for (int i = 0; i < 9; i++) {
// for (int j = 0; j < 9; j++) {
// System.out.print(board[i][j]+" ");
// }
// System.out.println();
// }
// }
map.clear();
boolean result = validateColumns(board,map);
if (!result){
System.out.println(false);
return;
}
map.clear();
result = validate9Cells(board,map);
System.out.println(result);
}
}
/**
* 校验九个小方格
* @param board
* @param map
*/
private static boolean validate9Cells(int[][] board, Map<Integer, Integer> map) {
for (int i = 0; i < 3; i++) {
for (int l = 0; l < 3; l++) {
map.clear();
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) {
int stone = board[i*3+j][l*3+k];
if (stone!= 0 && map.containsKey(stone)){
return false;
}
map.put(stone,0);
}
}
}
}
return true;
}
/**
* 校验列
* @param board
* @param map
*/
private static boolean validateColumns(int[][] board, Map<Integer, Integer> map) {
for (int i = 0; i < 9; i++) {
map.clear();
for (int j = 0; j < 9; j++) {
int stone = board[j][i];
if (stone != 0 && map.containsKey(stone)){
return false;
}
map.put(stone,0);
}
}
return true;
}
/**
* 初始化棋盘同时按行校验
* @param sudokuLines
* @param map
* @return
*/
private static int[][] initBoardAndValidateRows(String[] sudokuLines, Map<Integer, Integer> map) {
int[][] board = new int[9][9];
for (int i = 0; i < 9; i++) {
String line = sudokuLines[i];
final String[] stones = line.split(",");
map.clear();
for (int j = 0; j < 9; j++) {
board[i][j] = "-".equals(stones[j]) ? 0 : Integer.parseInt(stones[j]);
if (board[i][j]!= 0 && map.containsKey(board[i][j])){
System.out.println(false);
return new int[0][];
}
map.put(board[i][j],0);
}
}
return board;
}
}
//5,1,-,6,-,-,-,9,8 -,7,-,1,9,4,-,-,- -,-,-,-,-,-,-,6,- 8,-,-,4,-,-,7,-,- -,6,-,8,-,3,-,2,- -,-,3,-,-,1,-,-,6 -,3,-,-,-,-,-,4,- -,-,-,3,1,9,-,8,- 2,8,-,-,-,5,-,7,9
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