HDOJ-ACM1003(JAVA)

转载声明：原文转自http://www.cnblogs.com/xiezie/p/5502855.html

第一、二次的思路都是穷举；

第一次的实现是用二维数组；

import java.util.*;

import java.io.*;

public class Main{

    public static void main(String[] arg){
        Scanner scan = new Scanner(new BufferedInputStream(System.in));
        int n = scan.nextInt();
        int l = n;
        while(n!=0){
            int m = scan.nextInt();
            int[] a = new int[m];
            int len = 0;
            for(int i = 0 ; i != m ; i ++){
                a[i] = scan.nextInt();
                len = len + i + 1;
            }
            int[] sum = new int[len];
            for(int i = 0 ; i != m ; i ++ ){
                int h = 0;
                for(int g = 0 ; g != i+1 ; g ++ ){
                    h+=g;
                }
                for(int j = i ; j != m ; j ++ ){
                    for(int k = i ; k != j+1 ; k ++ ){
                        sum[m*i+j-h] = sum[m*i+j-h] + a[k];
                    }
                }
            }
            int max = sum[0];
            int maxI = 1,maxJ = 1;
            for(int i = 0 ; i != m ; i ++ ){
                int h = 0;
                for(int g = 0 ; g != i+1 ; g ++ ){
                    h+=g;
                }
                for(int j = i ; j != m ; j ++ ){
                    if(sum[m*i+j-h]>max){
                        maxI = i+1 ;
                        maxJ = j + 1;
                        max = sum[m*i+j-h];
                    }
                }
            }
            System.out.println("Case " + (l-n+1) + ":");
            System.out.println(max + " " + maxI  +  " " + maxJ);
            if(n!=1){
                System.out.println();
            }
            n--;
        }
    }

}

但是：报了Memory Limit Exceeded的错误

第二次的思路是将二维数组转化为一维数组

但是运行效果不好，代码冗长

第三次AC

具体分析这个程序应该怎么更好的实现，在输入时就开始判断最大数

import java.util.*;

import java.io.*;

public class Main{

    public static void main(String[] arg){
        Scanner scan = new Scanner(new BufferedInputStream(System.in));
        int n = scan.nextInt();
        int y = n;
        while(n!=0){
            int m = scan.nextInt();
            int l = m ;
            int sum = -1001;
            int max = -1001;
            int maxI = 1;
            int maxJ = 1;
            int i = 1;
            int j = 1;
            while(m!=0){
                int a = scan.nextInt();
                if(sum>=0){
                    j++;
                    sum += a ;
                }else{
                    i= l-m+1;
                    j= l-m+1;
                    sum = a;
                }
                if(max<sum){
                    max = sum;
                    maxI = i;
                    maxJ = j;
                }
                m--;
            }
            System.out.println("Case " + (y-n+1) + ":");
            System.out.println(max + " " + maxI + " " + maxJ);
            if(n!=1){
                System.out.println();
            }
            n--;
        }
    }

}