题解 | #种花#

import java.util.Scanner;

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

        while(in.hasNext()){
            // solution1(in);
            solution2(in);
        }
    }

    /**
     * 贪心
     * @param in
     */
    private static void solution2(Scanner in){
        int n = in.nextInt();

        int[] nums = new int[n+1];
        for(int i=1; i<=n; i++){
            nums[i] = in.nextInt();
        }

        int result = 0;
        for(int i=1; i+1<=n; i++){
            if(nums[i] > nums[i+1]){
                result += nums[i]-nums[i+1];
            }
        }

        result += nums[n];

        System.out.println(result);
    }

    /**
     * 动态规划
     * 
     * dp[i]表示前i个花园都完成计划至少需要的天数
     * 
     *         { dp[i-1]                       , nums[i] <= nums[i-1]
     * dp[i] = {
     *         { dp[i-1] + (nums[i]-nums[i-1]) , nums[i] > nums[i-1]
     *
     * @param in
     */
    private static void solution1(Scanner in){
        int n = in.nextInt();

        int[] nums = new int[n+1];
        for(int i=1; i<=n; i++){
            nums[i] = in.nextInt();
        }
        
        int[] dp = new int[n+1];
        dp[1] = nums[1];

        for(int i=2; i<=n; i++){
            if(nums[i] > nums[i-1]){
                dp[i] = dp[i-1] + nums[i] - nums[i-1];
            }else{
                dp[i] = dp[i-1];
            }
        }

        System.out.println(dp[n]);
    }
}