网上的题。剑指offer的。java
array: 待查找的二维数组 target:查找的数字
查找到返回true,查找不到返回false
原理(复制大牛的。可是他不是用java编的):从右上方的数字开始,若是该数字比查找的数字小,那么该数字所在行能够删除,不用继续考虑;若是该数字比查找的数字大,那么该数字所在列能够删除。这样,每次执行,都会删除一行或者一列,极端状况下,执行2n次。
package ab; /** * Created by dell on 2016/1/15. */ public class ab { public static final void main(String[] args) { //,[[1,2,8,9],[2,4,9,12],[4,7,10,13],[6,8,11,15]] //int[][] b = {{1, 2, 8,9}, {2,4, 9, 12}, {4,7, 10, 13},{6,8,11,15}}; int[][] b = {{1, 2, 8,9}, {2,4, 9, 12}, {4,7, 10, 13},{6,8,11,15}}; ab e = new ab(); int i = 5; e.Find(b, i); System.err.print("end1"); } public boolean Find(int[][] array, int target) { int m = array.length; int n = array[0].length; m--; n--; System.err.print(array[m-1][n-2]); int line = 0; int row = n; while (line < m && row > 0) { if (target > array[line][row]) { line++; } else if (target < array[line][row]) { row--; } else { return true; } } while (row==0 && line<=m ){ if (target > array[line][0]){ line++; }else if (target < array[line][0]){ return false; }else { return true; } } while (line ==m && row > 0){ if (target > array[m][row]){ return false; }else if (target < array[m][row]){ row--; }else { return true; } } return false; } }
调试截图一枚:数组