算法分析

初始化：f[0][0] = 0,f[0][1] = -INF

时间复杂度 $O(n)$

参考文献

算法提高课

Java 代码

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    static int N = 100010, INF = 0x3f3f3f3f;
    static int[] w = new int[N];
    static int[][] f = new int[N][2];
    static int n;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int T  = Integer.parseInt(br.readLine());
        while(T -- > 0)
        {
            n = Integer.parseInt(br.readLine());
            String[] s1 = br.readLine().split(" ");
            for(int i = 1;i <= n;i ++) w[i] = Integer.parseInt(s1[i - 1]);
            f[0][0] = 0;
            f[0][1] = -INF;
            for(int i = 1;i <= n;i ++)
            {
                f[i][0] = Math.max(f[i - 1][0], f[i - 1][1]);
                f[i][1] = f[i - 1][0] + w[i];
            }
            System.out.println(Math.max(f[n][0], f[n][1]));
        }
    }
}