Cyclic two-dimensional array maximum sub-array

I. Topics and Requirements

Title: Returns the number of the largest sub-arrays in a two-dimensional integer array.
Requirements:
Enter a two-dimensional shaping array with positive numbers in the array and a negative number.
A two-dimensional array is connected to the end of the line, like a belt.
One or more consecutive integers in an array make up a sub-array, each of which has a and.
The maximum value for the and of all sub-arrays. Requires a time complexity of O (n).

Second, the design idea

By solving the problem of the maximal subarray of a simple one-dimensional loopback array, the method we take is not an O (n) time-complexity algorithm. As for implementing an array loopback, our approach is to resolve the loopback by defining a twice-fold array to access two times to find the array.

Third, the source code

　　

1 /*======================================================================2 # Author:tianyongtao && Zhangyapeng3 # e-mail: [Email protected]4 # last modified:2015-04-01 10:145 # Filename:Demo.cpp6 # Description: Finding the largest subarray of two-dimensional loopback arrays7 ======================================================================*/8#include"stdafx.h"9# include <iostream>Ten# include <string> One# define MaxRow - A# define Maxcol - - using namespacestd; - intArr[maxrow][maxcol]; the intarray[maxrow][2*Maxcol]; - intSumarr (intX1,intY1,intX2,inty2)//Sub-array summation - { -     intsum=0; +      for(inti=x1;i<x2;i++) -     { +          for(intj=y1;j<y2;j++) A         { atsum+=Array[i][j]; -         } -     } -     returnsum; - } -  in voidLoadFile (intArr[][maxcol],int& Row,int&Col) - { toFILE * infile = fopen ("D:\\input.txt","R"); +     intnum[ -]; -     intCount=0; the     if(!infile) *     { $cout<<"file read failed!"<<Endl;Panax NotoginsengExit (-1); -     } the     Else +     { A         Charstr[Ten]; theFSCANF (infile,"%[^,]%*c", str); +Row =atof (str); -FSCANF (infile,"%[^,]%*c", str); $Col =atof (str); $          while(!feof (infile)) -         { -FSCANF (infile,"%[^,]%*c", str); thenum[count++]=atof (str); -         }Wuyi     } the      for(inti=row-1; i>=0; i--) -     { Wu          for(intj=col-1; j>=0; j--) -         { Aboutarr[i][j]=num[--Count]; $         } -     } -      for(intI=0; i<row;i++) -     { A          for(intj=0; j<col;j++) +         { theARRAY[I][J] =Arr[i][j]; -Array[i][j+col] =Arr[i][j]; $         } the     } the } the  the //test function - intMain () in { the     introw=0; the     intCol=0; About LoadFile (arr,row,col); the      for(intI=0; i<row;i++) the     { the          for(intj=0; j<col;j++) +         { -cout<<arr[i][j]<<"\ t"; the         }Bayicout<<Endl; the     } the     intX1,y1;//represents the horizontal ordinate of the upper left corner point -     intX2,y2;//represents the horizontal ordinate of the upper right corner point -     intFLAG1,FLAG2,FLAG3,FLAG4;//(FLAG1,FLAG2) identifies the upper-left coordinate (FLAG3,FLAG4) of the largest subarray to identify the lower-right coordinate of the largest subarray theflag1=flag2=flag3=flag4=0; the     intmax = array[0][0];//max value during storage comparison the      for(x1=0; x1<row;x1++) the     { -          for(y1=0; y1<col;y1++) the         { the              for(x2=x1+1; x2<=row;x2++) the             {94                  for(y2=y1+1; y2<=2*col;y2++) the                 { the                     if((y2-y1) >Col) the                     {98                          Break; About                     } -                     if(Sumarr (X1,y1,x2,y2) >max)101                     {102Max =Sumarr (x1,y1,x2,y2);103flag1=X1;104Flag2=Y1; theflag3=x2;106flag4=Y2;107                     }108                 }109             } the         }111     } thecout<<"the maximum number of sub-arrays is:"<<Endl;113      for(inti=flag1;i<flag3;i++) the     { the          for(intj=flag2;j<flag4;j++) the         {117cout<<array[i][j]<<"\ t";118         }119cout<<Endl; -     }121cout<<"The number of the largest sub-arrays is:"<<max<<Endl;122     return 0;123}

Iv. Results of operation

1. File contents

　　　　

2. Running Results

　　　　

V. Results test

1. Full positive

　　

2. All negative

　　

3. There is a positive negative

　　

Six, experience

The program in the implementation of only the last two-dimensional array of the largest sub-array to make a small change, the implementation of the method does not have much change, the only regret is that there is no time to achieve the complexity of O (n).

In the process of knot group development, I cooperate with Tian Yongtao more and more tacit understanding, can improve the development efficiency to a certain extent.

　　

Cyclic two-dimensional array maximum sub-array