GeeksforGeeks » Miscellaneous
Print the matrix in a sorted order
(4 posts)-
Given a m*n matrix that is sorted row-wise and column-wise. How would you print the entire matrix in a sorted order ?
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One straightforward way is to divide the matrix in two and recursively merge rows (or columns). Print the final merged result.
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For the above example:
1) Merge first two rows and last two rows.
2) Finally, merge the merged arrays (obtained in step 1), and print the resultant array. -
#include <stdio.h> #define ROWS 3 #define COLS 5 void swap(int *a, int *b) { /*swap numbers a & b*/ int temp = *a; *a = *b; *b = temp; } void print_array(int *arr) { /*prints the two dimensional array arr*/ int i,j; for(i=0;i<ROWS;i++) { for(j=0;j<COLS;j++) { printf(" %d ",arr[COLS*i + j]); } printf("\n"); } } int min(int a, int b) { /*Finds the minimum of a and b*/ if(a<b) return a; return b; } void adjustrow(int *arr,int cur_row,int cur_col) { /*adjusts the row in ascending order*/ if(arr[COLS*cur_row + cur_col+1] >= arr[COLS*cur_row + cur_col]) //elem in next column is greater return; swap(&arr[COLS*cur_row + cur_col+1],&arr[COLS*cur_row + cur_col]); adjustrow(arr,cur_row,cur_col+1); } void adjustcol(int *arr,int cur_row,int cur_col) { /*adjusts the column in asceding order*/ if(arr[COLS*(cur_row+1) + cur_col] >= arr[COLS*cur_row + cur_col]) //elem in next row is greater return; swap(&arr[COLS*(cur_row+1) + cur_col],&arr[COLS*cur_row + cur_col]); adjustcol(arr,cur_row+1,cur_col); } void readjust(int *arr,int cur_row, int cur_col) { /*re-adjusts the array so that the initial property of ascending rows and columns is maintained*/ if(cur_row == ROWS-1) //into the last row { adjustrow(arr,cur_row,cur_col); return; } if(cur_col == COLS -1) //into the last column { adjustcol(arr,cur_row,cur_col); return; } //new elem in right place if(arr[COLS*cur_row + cur_col] <= min(arr[COLS*(cur_row+1) + cur_col],arr[COLS*(cur_row) + cur_col+1])) return; int new_cur_row = arr[COLS*(cur_row+1) + cur_col] <= arr[COLS*cur_row + cur_col+1] ? (cur_row+1) : cur_row; int new_cur_col = arr[COLS*(cur_row+1) + cur_col] <= arr[COLS*cur_row + cur_col+1] ? cur_col : (cur_col+1); swap(&arr[COLS*cur_row + cur_col],&arr[COLS*new_cur_row + new_cur_col]); readjust(&arr[0],new_cur_row,new_cur_col); } void sort_whole_array(int *arr) { /*interface function for sorting the complete array*/ int i,j; for(i=0;i<ROWS-1;i++) { for(j=1;j<COLS;j++) { if(arr[COLS*i + j] <= arr[COLS*(i+1) + 0]) //arr[i][j] <= arr[i+1][0] continue; swap(&arr[COLS*i + j],&arr[COLS*(i+1) + 0]); //swap(&arr[i][j],&arr[i+1][0]) readjust(&arr[0],(i+1),0); //readjust(&arr[i+1][0],i+1,0); } } } int main() { int arr[ROWS][COLS] = {{1,3,4,8,9},{2,5,18,25,50},{6,7,22,45,55}}; printf("\n==Input Array==\n"); print_array(&arr[0][0]); sort_whole_array(&arr[0][0]); printf("\n==Sorted Array==\n"); print_array(&arr[0][0]); return 0; }
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