题解 | 拦截导弹

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> heights(n);
    for(int i = 0; i < n; i++) {
        cin >> heights[i];
    }
    
    // 求最长非递增子序列
    vector<int> dp(n, 1);
    int maxLen = 1;
    for(int i = 1; i < n; i++) {
        for(int j = 0; j < i; j++) {
            if(heights[j] >= heights[i]) {
                dp[i] = max(dp[i], dp[j] + 1);
            }
        }
        maxLen = max(maxLen, dp[i]);
    }
    
    // 求最少系统数
    vector<int> systems;
    for(int height : heights) {
        bool placed = false;
        for(int& last : systems) {
            if(last >= height) {
                last = height;
                placed = true;
                break;
            }
        }
        if(!placed) {
            systems.push_back(height);
        }
    }
    
    cout << maxLen << endl << systems.size() << endl;
    return 0;
}

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] heights = new int[n];
        for(int i = 0; i < n; i++) {
            heights[i] = sc.nextInt();
        }
        
        // 求最长非递增子序列
        int[] dp = new int[n];
        Arrays.fill(dp, 1);
        int maxLen = 1;
        for(int i = 1; i < n; i++) {
            for(int j = 0; j < i; j++) {
                if(heights[j] >= heights[i]) {
                    dp[i] = Math.max(dp[i], dp[j] + 1);
                }
            }
            maxLen = Math.max(maxLen, dp[i]);
        }
        
        // 求最少系统数
        List<Integer> systems = new ArrayList<>();
        for(int height : heights) {
            boolean placed = false;
            for(int i = 0; i < systems.size(); i++) {
                if(systems.get(i) >= height) {
                    systems.set(i, height);
                    placed = true;
                    break;
                }
            }
            if(!placed) {
                systems.add(height);
            }
        }
        
        System.out.println(maxLen);
        System.out.println(systems.size());
        sc.close();
    }
}

n = int(input())
heights = list(map(int, input().split()))

# 求最长非递增子序列
dp = [1] * n
max_len = 1
for i in range(1, n):
    for j in range(i):
        if heights[j] >= heights[i]:
            dp[i] = max(dp[i], dp[j] + 1)
    max_len = max(max_len, dp[i])

# 求最少系统数
systems = []
for height in heights:
    placed = False
    for i in range(len(systems)):
        if systems[i] >= height:
            systems[i] = height
            placed = True
            break
    if not placed:
        systems.append(height)

print(max_len)
print(len(systems))