3.1 classroom exercises

Question: return the sum of the largest subarrays in a two-dimensional integer array.

Requirements:

Enter a two-dimensional integer array with positive or negative values.

A child matrix in a two-dimensional array forms a sub-array, and each sub-array has a sum.

Returns the maximum value of the sum of all sub-arrays. The time complexity is O (n ).

Thinking process: the biggest array of two-dimensional arrays is extended from one-dimensional arrays. First, determine the maximum upper and lower bounds and determine the maximum range of sub-arrays from the first line, for the range of the specified maximum sub-array, divide the maximum sub-array into several different rows according to the number of columns. For the arrays generated above, to obtain the maximum sum of sub-arrays.

1 # include <iostream> 2 using namespace STD; 3 void main () 4 {5 int A, B, I, J, m = 0, a [0, 100] [100]; 6 7 cout <"input matrix rows and columns"; 8 CIN> A> B; 9 if (a> 100 | B> 100) 10 {11 cout <"Enter again:"; 12 CIN> A> B; 13} 14 for (I = 0; I <A; I ++) 15 {16 for (j = 0; j <B; j ++) 17 {18 CIN> A [I] [J]; 19} 20 21} 22 int sum [100] = {0}, max = 0, result = A [0] [0]; 23 24 for (I = 0; I <A; I ++) 25 {26 while (m + I <A) 27 {28 for (j = 0; j <B; j ++) 29 {30 sum [J] = sum [J] + A [M + I] [J]; 31 32} 33 max = 0; 34 for (j = 0; j <B; j ++) 35 {36 IF (MAX + sum [J]> sum [J]) 37 {38 max = MAX + sum [J]; 39} 40 else41 {42 max = sum [J]; 43} 44 If (max> result) 45 {46 result = max; 47} 48} 49 m ++; 50} 51 m = 0; 52 for (j = 0; j <B; j ++) 53 {54 sum [J] = 0; 55} 56 57} 58 59 cout <result; 60}

Perception

: Each input code is a learning process, and problems can only be found after being done.

 

3.1 classroom exercises