网易真题之回文序列

题目描述：

分析：

比较第一个和最后一个，如果第一个大，则最后两个相加替换原来位置。如果首尾元素相等，则删除首尾元素。

package project001;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main07 {

public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int nums = in.nextInt();
List<Integer> list = new ArrayList<Integer>();

for(int i=0;i<nums;i++){
list.add(in.nextInt());
}
System.out.println(getSum(list));

}
public static int getSum(List<Integer> list){
if(list.size()<=1) return 0;
int operation = 0;
while(list.size()>1){
if(list.get(0)>list.get(list.size()-1)){
int a = list.get(list.size()-2);
int b = list.get(list.size()-1);
list.set(list.size()-2, a+b);
list.remove(list.size()-1);
operation++;
}else if(list.get(0)<list.get(list.size()-1)){
int a = list.get(0);
int b = list.get(1);
list.set(0, a+b);
list.remove(1);
operation++;
}else{
list.remove(0);
list.remove(list.size()-1);
}
}
return operation;
}
}