[PAT-A] 1051 Pop Sequence

Java

import java.util.Scanner;
import java.util.Stack;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int m = scanner.nextInt();  // 栈容量
        int n = scanner.nextInt();  // 数字数量
        int k = scanner.nextInt();  // 测试例数量

        while (k-- > 0) {
            Stack<Integer> stack = new Stack<>();
            int[] num = new int[n];
            for (int i = 0; i < n; ++i) {
                num[i] = scanner.nextInt();
            }

            int pos = 0;
            boolean flag = false;
            for (int i = 1; i <= n; ++i) {
                stack.push(i);
                if (stack.size() > m) {
                    flag = true;
                    break;
                }
                while (!stack.isEmpty() && num[pos] == stack.peek()) {
                    ++pos;
                    stack.pop();
                }
            }

            if (!flag && stack.isEmpty()) {
                System.out.println("YES");
            } else {
                System.out.println("NO");
            }
        }

        scanner.close();
    }
}

C++

#include <iostream>
#include <cstring>
#include <algorithm>
#include <stack>

using namespace std;

const int MAXN = 1010;

int m, n, k;         // m: 栈容量，n: 数字，k: 测试例数量

int main(void) {
    cin >> m >> n >> k;

    while (k--) {
        stack<int> s;
        int num[MAXN];
        for (int i = 0; i < n; ++i) cin >> num[i];

        int pos = 0, flag = 0;
        for (int i = 1; i <= n; ++i) {
            s.push(i);
            if (s.size() > m) {
                flag = 1;
                break;
            }
            while (!s.empty() && num[pos] == s.top()) {
                ++pos;
                s.pop();
            }
        }

        if (flag == 0 && s.empty()) printf("YES\n");
        else printf("NO\n");
    }

    return 0;
}