leetCode/src/list/FindNumberIn2DArray.java

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package list;
/**
* @apiNote 在一个 n * m 的二维数组中,每一行都按照从左到右递增的顺序排序,每一列都按照从上到下递增的顺序排序。
* 请完成一个函数,输入这样的一个二维数组和一个整数,判断数组中是否含有该整数。
* 示例:
* 现有矩阵 matrix 如下:
* [
* [1, 4, 7, 11, 15],
* [2, 5, 8, 12, 19],
* [3, 6, 9, 16, 22],
* [10, 13, 14, 17, 24],
* [18, 21, 23, 26, 30]
* ]
* 给定 target = 5返回 true。
* 给定 target = 20返回 false。
*
* @author zeekling
* @version 1.0
* @date 2020-03-31
*/
public class FindNumberIn2DArray{
public boolean findNumberIn2DArray(int[][] matrix, int target) {
if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
return false;
}
int rows = matrix.length, columns = matrix[0].length;
int row = 0, column = columns - 1;
while (row < rows && column >= 0) {
int num = matrix[row][column];
if (num == target) {
return true;
} else if (num > target) {
column--;
} else {
row++;
}
}
return false;
}
}