剑指04 二维数组中的查找

剑指04 二维数组中的查找

解法一：蛮力法

class Solution {
    public boolean findNumberIn2DArray(int[][] matrix, int target) {
        if (matrix == null || matrix.length == 0 || matrix[0].length == 0)
            return false;
        for (int i = 0; i < matrix.length; i++)
            for (int j = 0; j < matrix[0].length; j++)
                if (matrix[i][j] == target)
                    return true;
        return false;
    }
}

解法二：优化版

class Solution {
    public boolean findNumberIn2DArray(int[][] matrix, int target) {
        if (matrix == null || matrix.length == 0 || matrix[0].length == 0)
            return false;
        int row = 0, col = matrix[0].length - 1;
        while (row < matrix.length && col >= 0) {
            if (matrix[row][col] == target)
                return true;
            else if (matrix[row][col] > target)
                --col;
            else 
                ++row;
        }
        return false;
    }
}