Problem:
Score : 100 points

Problem Statement

Taro's summer vacation starts tomorrow, and he has decided to make plans for it now.

The vacation consists of N days.
For each i (1 \leq i \leq N), Taro will choose one of the following activities and do it on the i-th day:

A: Swim in the sea. Gain a_i points of happiness.

B: Catch bugs in the mountains. Gain b_i points of happiness.

C: Do homework at home. Gain c_i points of happiness.

As Taro gets bored easily, he cannot do the same activities for two or more consecutive days.

Find the maximum possible total points of happiness that Taro gains.

Constraints

All values in input are integers.

1 \leq N \leq 10^5

1 \leq a_i, b_i, c_i \leq 10^4

Input

Input is given from Standard Input in the following format:

N
a_1 b_1 c_1
a_2 b_2 c_2
:
a_N b_N c_N

Output

Print the maximum possible total points of happiness that Taro gains.

Sample Input 1

3
10 40 70
20 50 80
30 60 90

Sample Output 1

210

If Taro does activities in the order C, B, C, he will gain 70 + 50 + 90 = 210 points of happiness.

Sample Input 2

1
100 10 1

Sample Output 2

100

Sample Input 3

7
6 7 8
8 8 3
2 5 2
7 8 6
4 6 8
2 3 4
7 5 1

Sample Output 3

46

Taro should do activities in the order C, A, B, A, C, B, A.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)



import java.io.IOException;
import java.io.InputStream;
import java.util.*;
import java.util.List;
import java.util.stream.IntStream;


public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner();
        int n=scanner.nextInt();
        int[] a=new int[n];
        int[] b=new int[n];
        int[] c=new int[n];
        for(int i=0;i<n;i++){
            a[i]=scanner.nextInt();
            b[i]=scanner.nextInt();
            c[i]=scanner.nextInt();
        }

        int[][] dp=new int[3][n+1];
        for(int i=1;i<n+1;i++){
            dp[0][i]=max(dp[1][i-1],dp[2][i-1])+a[i-1];
            dp[1][i]=max(dp[0][i-1],dp[2][i-1])+b[i-1];
            dp[2][i]=max(dp[0][i-1],dp[1][i-1])+c[i-1];
        }
        put(max(dp[0][n],max(dp[1][n],dp[2][n])));

    }





    public static int upper_bound(int[] a,int val){
        return upper_bound(a,0,a.length,val);
    }
    public static int upper_bound(int[] a,int l,int r,int val){
        if(r-l==1){
            if(a[l]>val) return l;
            return r;
        }
        int mid=(l+r)/2;
        if(a[mid]>val){
            return upper_bound(a,l,mid,val);
        }else{
            return upper_bound(a,mid,r,val);
        }
    }
    public static int lower_bound(int[] a,int val){
        return lower_bound(a,0,a.length,val);
    }
    public static int lower_bound(int[] a,int l,int r,int val){
        if(r-l==1){
            if(a[l]<val) return r;
            return l;
        }
        int mid=(l+r)/2;
        if(a[mid]<val){
            return lower_bound(a,mid,r,val);
        }else{
            return lower_bound(a,l,mid,val);
        }

    }


    public static int max(int a,int b){
        return Math.max(a,b);
    }
    public static long max(long a,long b){
        return Math.max(a,b);
    }
    public static int min(int a,int b){
        return Math.min(a,b);
    }
    public static long min(long a,long b){
        return Math.min(a,b);
    }
    public static int abs(int a){
        return Math.abs(a);
    }
    public static long abs(long a){
        return Math.abs(a);
    }
    public static void print(Object object){
        System.out.print(object);
    }
    public static void put(Object object) {
        System.out.println(object);
    }
    public static void put(){
        System.out.println();
    }
    public static String format(String string, Object... args) {
        return String.format(string, args);
    }
}

final class Scanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;

    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        } else {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }

    private int readByte() {
        if (hasNextByte())
            return buffer[ptr++];
        else
            return -1;
    }

    private boolean isPrintableChar(int c) {
        return 33 <= c && c <= 126;
    }

    public boolean hasNext() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr]))
            ptr++;
        return hasNextByte();
    }

    public String next() {
        if (!hasNext())
            throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    public long nextLong() {
        if (!hasNext())
            throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while (true) {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            } else if (b == -1 || !isPrintableChar(b)) {
                return minus ? -n : n;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE)
            throw new NumberFormatException();
        return (int) nl;
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }
}
final class FixedPair {
    final private int x, y;
    final static public FixedPair ZEROS=new FixedPair(0,0);
    FixedPair(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    @Override
    public int hashCode() {
        return x+y;
    }

    @Override
    public boolean equals(Object obj) {
        boolean result=super.equals(obj);
        if(obj.getClass()!=this.getClass()){
            return false;
        }
        FixedPair pair=(FixedPair)obj;
        if(this.x==pair.x&&this.y==pair.y) return true;
        return false;
    }

    @Override
    public String toString() {
        return String.format("(%d,%d)", x, y);
    }
}
final class Tuple<T,V>{
    //immutabl1でないことに注意(T,Vがmutableの場合変更可能)
    final private T t;
    final private V v;
    Tuple(T t,V v){
        this.t=t;
        this.v=v;
    }

    public T getT() {
        return t;
    }

    public V getV() {
        return v;
    }

    @Override
    public int hashCode() {
        return (t.hashCode()+v.hashCode());
    }

    @Override
    @SuppressWarnings("unchecked")
    public boolean equals(Object obj) {
        if(obj.getClass()!=this.getClass()){
            return false;
        }
        Tuple<T,V> tuple=(Tuple<T, V>) obj;
        return tuple.t.equals(this.t)&&tuple.v.equals(this.v);
    }

    @Override
    public String toString() {
        return String.format("<Tuple>=<%s,%s>",t,v);
    }
}
final class LowerBoundComparator<T extends Comparable<? super T>>
        implements Comparator<T>
{
    public int compare(T x, T y)
    {
        return (x.compareTo(y) >= 0) ? 1 : -1;
    }
}

final class UpperBoundComparator<T extends Comparable<? super T>>
        implements Comparator<T>
{
    public int compare(T x, T y)
    {
        return (x.compareTo(y) > 0) ? 1 : -1;
    }
}
final class Util {
    static long gcd(long a,long b){
        //最大公約数　
        if(a%b==0)return b;
        return gcd(b,a%b);
    }
    static long lcm(long a,long b){
        //最小公倍数
        long gcd=gcd(a,b);
        long result=b/gcd;
        return a*result;
    }
    static long kaijoMod(int n,int mod){
        if(n<1) return -1;
        long result=1;
        for(int i=n;i>1;i--){
            result*=i;
            result%=mod;
        }
        return result;
    }
    static <T extends Comparable<T>> Map<T,Integer> count(List<T> list){
        //副作用
        Collections.sort(list);
        Map<T,Integer> result=new HashMap<>();
        int l=0,r=0;
        while(l<list.size()){
            while(r<list.size()-1&&list.get(r).equals(r+1)){
                r++;
            }
            result.put(list.get(r),r-l+1);
            r++;
            l=r;
        }
        return result;

    }
    static Map<Integer,Integer> count(int[] array){
        //副作用
        Arrays.sort(array);
        Map<Integer,Integer> result=new HashMap<>();
        int l=0,r=0;
        while(l<array.length){
            while(r<array.length-1&&array[r]==array[r+1]){
                r++;
            }
            result.put(array[l],r-l+1);
            r++;
            l=r;
        }
        return result;
    }
    static <T> String toStringBWS(Iterable<T> iterable){
        Iterator<T> ite=iterable.iterator();
        return toStringBWS(ite);
    }
    static <T> String toStringBWS(Iterator<T> ite){
        StringBuilder sb=new StringBuilder();
        sb.append(ite.next());
        while(ite.hasNext()){
            sb.append(" ");
            sb.append(ite.next());
        }
        return sb.toString();
    }
    static int[] factoringInPrimeNumbers(long n,int size){
        //素因数分解
        //sizeがnに比べて小さい場合完全に素因数分解出来ていない可能性がある
        int[] result=new int[size];
        for(int i=2;n>1&&i< result.length;i++){
            while(n%i==0){
                result[i]++;
                n/=i;
            }
        }
        return result;

    }
}