2982611_ac_1888ms_5272k.java

北大大牛代码 1240道题的原代码 超级权威

import java.util.*;

public class Main {
	
	public static void main(String[] args) {
		
		Scanner cin = new Scanner (System.in);
		int i, j, ans, n, k;
		boolean c;
		int m;
		int t[] = new int [150001];
		
		ans = 0;
		n = cin.nextInt();
		for(i = 1; i <= n; i++)
		{
			t[i] = cin.nextInt();
		}
		k = 1;i = 1;
		c = true;m = 0;
		while(i <= n)
		{
			if(k%2!=0)
			{
				c = true;
				for(j = i; j < n; j++)
				{
					if(t[j]>t[j+1])
						break;
				}
				ans += t[j];
				i = j+1;
			}
			else
			{
				c = false;
				for(j = i; j < n; j++)
				{
					if(t[j]<t[j+1])
						break;
				}
				ans -= t[j];
				m = t[j];
				i = j+1;
			}
			k++;
		}
		if(!c)
			ans += m;
		System.out.println(ans);
	}
}