Algorithm Note _130: Lookup of row and column increment matrices (Java)

Directory

1 Problem Description

2 Solutions

2.1 Positioning Method

  1 problem description

in a two-dimensional array of M row n columns, each row is arranged in ascending order from left to right, and each column is arranged in ascending order from top to bottom. Now that you have entered such a two-dimensional array and an integer, complete a function that determines whether the array contains the integer.

2 Solutions 2.1 Positioning method

the time complexity of the algorithm below is O (M + N), space complexity is O (1).

The specific code is as follows:

Package Com.liuzhen.practice; Public classMain { PublicBoolean Youngmatrix (int[] A,intkey) {        inti =0, j = a[0].length-1; inttemp =A[i][j];  while(true) {            if(temp = =key) {                return true; } Else if(Temp < key && I < a.length-1) {Temp= a[++i]            [j]; } Else if(Temp > key && J >0) {Temp= a[i][--J]; } Else {                return false; }        }    }         Public Static voidMain (string[] args) {main test=NewMain (); int[] A = {{1,2,8,9},{2,4,9, A},{4,7,Ten, -},{6,8, One, the}}; if(Test. Youngmatrix (A,6) ) System. out. println ("The matrix A contains element 6"); ElseSystem. out. println ("element 6 is not included in matrix a"); if(Test. Youngmatrix (A,5) ) System. out. println ("The matrix A contains element 5"); ElseSystem. out. println ("element 5 is not included in matrix a"); }}

Operation Result:

Matrix A contains element 6 matrix A does not contain element 5

Resources:

1."Programming method interview and algorithmic experience" July

Algorithm Note _130: Lookup of row and column increment matrices (Java)