字符串处理
286. 数组拼接
坑比用例
3
2
2,5,6,7,,,9,5,7
1,7,4,3,,4
import java.util.Scanner;
import java.util.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int Len = Integer.parseInt(in.nextLine());
int count = Integer.parseInt(in.nextLine());
List<List<Integer>> lists = new ArrayList<>();
List<Integer> res = new ArrayList<>();
for (int i = 0; i < count; i++) { // 堆每行进行
String[] split = in.nextLine().split("[,]+"); // 处理多逗号的情况
int tempLen = split.length; // 长度
for (int j = 0; j < tempLen && j < Len; j++) { // 收入结果中
res.add(Integer.parseInt(split[j]));
}
ArrayList<Integer> temp = new ArrayList<>();
for (int j = Len; j < split.length; j++) {
temp.add(Integer.parseInt(split[j]));
}
if (temp.size() != 0){
lists.add(temp);
}
}
int sum = 0;
for (List<Integer> list : lists) {
if (list.size() != 0){
sum++;
}
}
getResult(sum, lists, res, Len);
StringBuilder ans = new StringBuilder();
for (Integer re : res) {
ans.append(re + ",");
}
System.out.println(ans.substring(0, ans.length() - 1));
}
public static void getResult(int sum, List<List<Integer>> lists, List<Integer> res, int len){
if (sum == 0){
return;
}
for (int i = 0; i < lists.size(); i++) {
List<Integer> list = lists.get(i);
int size = list.size();
if (size == 0){
continue;
}
for (int j = 0; j < size && j < len; j++) {
res.add(list.get(j));
}
if (size <= len){
lists.set(i, new ArrayList<>());
sum--;
}else { // 比你要拿的长
for (int j = 0; j < len; j++) {
list.remove(0);
}
lists.set(i, list);
}
}
getResult(sum, lists, res, len);
}
}
使用 subList 进行优化
import java.util.Scanner;
import java.util.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int Len = Integer.parseInt(in.nextLine());
int count = Integer.parseInt(in.nextLine());
List<List<Integer>> lists = new ArrayList<>();
List<Integer> res = new ArrayList<>();
for (int i = 0; i < count; i++) { // 堆每行进行
String[] split = in.nextLine().split("[,]+");
int tempLen = split.length; // 长度
for (int j = 0; j < tempLen && j < Len; j++) { // 收入结果中
res.add(Integer.parseInt(split[j]));
}
ArrayList<Integer> temp = new ArrayList<>();
for (int j = Len; j < split.length; j++) {
temp.add(Integer.parseInt(split[j]));
}
if (temp.size() != 0){
lists.add(temp);
}
}
int sum = 0;
for (List<Integer> list : lists) {
if (list.size() != 0){
sum++;
}
}
getResult(sum, lists, res, Len);
StringBuilder ans = new StringBuilder();
for (Integer re : res) {
ans.append(re + ",");
}
System.out.println(ans.substring(0, ans.length() - 1));
}
public static void getResult(int sum, List<List<Integer>> lists, List<Integer> res, int len){
if (sum == 0){
return;
}
for (int i = 0; i < lists.size(); i++) {
List<Integer> list = lists.get(i);
int size = list.size();
if (size == 0){
continue;
}
for (int j = 0; j < size && j < len; j++) { // 添加操作！！！
res.add(list.get(j));
}
if (size <= len){
list.clear();
sum--;
}else { // 比你要拿的长
list.subList(0, len).clear(); // 引用类型
}
}
getResult(sum, lists, res, len);
}
}
271. 矩阵元素的边界值
[[1,2],[3,4]] # 处理成矩阵
import java.util.Scanner;
import java.util.*;
import java.util.regex.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
static int row;
static int col;
static int[][] arr;
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String s = in.nextLine();
String[] split = s.substring(2, s.length() - 2).split("\\],\\["); // 巧妙的分割
row = split.length;
col = split[0].split(",").length;
arr = new int[row][col];
int index = 0;
String[] temp = s.replaceAll("[\\[\\]]", "").split(",");
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
arr[i][j] = Integer.parseInt(temp[index++]);
}
}
List<Integer> list = new ArrayList<>();
for (int i = 0; i < col; i++) {
int max = Integer.MIN_VALUE; // 要求最大值，就先定义为 MIN_VALUE
for (int j = 0; j < row; j++) {
max = Math.max(max, arr[j][i]);
}
list.add(max);
}
System.out.println(Collections.min(list));
}
}
125. 最长的完全交替连续方波信号
import java.util.Scanner;
import java.util.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String s = in.nextLine() + "0"; // 判断最后一位是否符合
char[] chars = s.toCharArray();
int count = 0; // 连续 0 的个数
ArrayList<List<Character>> list = new ArrayList<>();
ArrayList<Character> temp = new ArrayList<>();
for (int i = 0; i < chars.length; i++) {
char aChar = chars[i];
if (aChar == '0') {
if (count == 0) {
count++;
temp.add(aChar);
} else { // 连续 0 超过 1
if (temp.size() > 1) {
list.add(new ArrayList<>(temp));
temp.clear();
temp.add(aChar);
} else {
temp.clear();
temp.add(aChar);
}
}
continue;
}
// 当前字符为 1 的情形
count = 0;
temp.add(aChar);
}
ArrayList<List<Character>> res = new ArrayList<>();
for (List<Character> characters : list) {
if (isValid(characters)) {
res.add(characters);
}
}
if (res.size() == 0){
System.out.println(-1);
return;
}
List<Character> max = Collections.max(res, (o1, o2) -> o1.size() - o2.size());
max.stream().forEach(character -> System.out.print(character));
}
public static boolean isValid(List<Character> list){
int count = 0; // 连续 1 的个数
for (Character character : list) {
if (character == '1'){
count++;
if (count > 1){
return false;
}
}else {
count = 0;
}
}
return true;
}
}
