CT
[BOJ] 18단계 스택
kinggora
2023. 4. 13. 20:41
| 1 | 10828 | 스택 |
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(reader.readLine());
CustomStack stack = new CustomStack();
for(int i = 0; i < n; i++) {
String[] split = reader.readLine().split(" ");
switch (split[0]) {
case "push":
stack.push(Integer.parseInt(split[1]));
break;
case "pop":
System.out.println(stack.pop());
break;
case "size":
System.out.println(stack.size());
break;
case "empty":
System.out.println(stack.empty());
break;
case "top":
System.out.println(stack.top());
break;
}
}
}
private static class CustomStack {
private final List<Integer> store = new ArrayList<>();
public void push(int X) {
store.add(X);
}
public int pop() {
if(store.isEmpty()) {
return -1;
} else {
return store.remove(store.size() - 1);
}
}
public int size() {
return store.size();
}
public int empty() {
if(store.isEmpty()) {
return 1;
} else {
return 0;
}
}
public int top() {
if(store.isEmpty()) {
return -1;
} else {
return store.get(store.size() - 1);
}
}
}
}*스택 -> ArrayList로 구현
| 2 | 10773 | 제로 |
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int k = Integer.parseInt(reader.readLine());
int[] stack = new int[k+1];
int top = -1;
for(int i = 0; i < k; i++) {
int num = Integer.parseInt(reader.readLine());
if(num == 0) {
stack[top] = 0;
top--;
} else {
top++;
stack[top] = num;
}
}
int sum = 0;
for(int i = 0; i <= top; i++) {
sum += stack[i];
}
System.out.println(sum);
}
}*스택 -> 배열로 구현
| 3 | 9012 | 괄호 |
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int T = Integer.parseInt(reader.readLine());
StringBuilder sb = new StringBuilder();
for(int i = 0; i < T; i++) {
List<String> stack = new ArrayList<>();
String str = reader.readLine();
boolean underflow = false;
for(int j = 0; j < str.length(); j++) {
if(str.charAt(j) == '(') {
stack.add("(");
} else if(stack.isEmpty()) {
underflow = true;
break;
} else {
stack.remove(stack.size() - 1);
}
}
if(!underflow && stack.isEmpty()) {
sb.append("YES");
} else {
sb.append("NO");
}
sb.append("\n");
}
System.out.print(sb);
}
}*underflow 고려
| 4 | 4949 | 균형잡힌 세상 |
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
StringBuilder sb = new StringBuilder();
while(true) {
String str = reader.readLine();
if(str.equals(".")) {
break;
}
List<String> stack = new ArrayList<>();
boolean isValanced = true;
for(int i = 0; i < str.length(); i++) {
String s = String.valueOf(str.charAt(i));
if(!"([)]".contains(s)) {
continue;
}
if("([".contains(s)) {
stack.add(s);
} else if(stack.isEmpty()) {
isValanced = false;
break;
} else {
String element = stack.remove(stack.size() - 1);
if(s.equals(")") && !element.equals("(")){
isValanced = false;
break;
} else if(s.equals("]") && !element.equals("[")){
isValanced = false;
break;
}
}
}
if(isValanced && stack.isEmpty()) {
sb.append("yes");
} else {
sb.append("no");
}
sb.append("\n");
}
System.out.print(sb);
}
}
| 5 | 1874 | 스택 수열 |
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(reader.readLine());
int[] sequence = new int[n];
for(int i = 0; i < n; i++) {
sequence[i] = Integer.parseInt(reader.readLine());
}
CustomStack stack = new CustomStack();
StringBuilder sb = new StringBuilder();
int index = 0;
int value = 1;
while(index < n) {
if(sequence[index] != stack.top()) {
if(value > n) {
System.out.println("NO");
return;
} else {
stack.push(value);
value++;
sb.append("+").append("\n");
}
} else {
stack.pop();
index++;
sb.append("-").append("\n");
}
}
System.out.print(sb);
}
static class CustomStack {
List<Integer> stack = new ArrayList<>();
public void push(int x) {
stack.add(x);
}
public int pop() {
if(stack.isEmpty()) {
return -1;
}
return stack.remove(stack.size() - 1);
}
public int top() {
if(stack.isEmpty()) {
return -1;
}
return stack.get(stack.size() - 1);
}
}
}import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(reader.readLine());
CustomStack stack = new CustomStack();
StringBuilder sb = new StringBuilder();
int value = 1;
for(int i = 0; i < n; i++) {
int input = Integer.parseInt(reader.readLine());
if(stack.top() != input && value <= n) {
while(value <= input) {
stack.push(value);
value++;
sb.append("+").append("\n");
}
} else if(stack.isEmpty()){
System.out.println("NO");
return;
}
if(stack.top() == input){
stack.pop();
sb.append("-").append("\n");
}
}
if(stack.isEmpty()) {
System.out.print(sb);
} else {
System.out.println("NO");
}
}
static class CustomStack {
List<Integer> stack = new ArrayList<>();
public void push(int x) {
stack.add(x);
}
public int pop() {
if(stack.isEmpty()) {
return -1;
}
return stack.remove(stack.size() - 1);
}
public int top() {
if(stack.isEmpty()) {
return -1;
}
return stack.get(stack.size() - 1);
}
public boolean isEmpty() {
if(stack.isEmpty()) {
return true;
}
return false;
}
}
}