240. Search a 2D Matrix II

思路: 從右上角開始看, 如右上角大於target , 向左一行看, j--,
如該數等於target, return true,
如該數小於target, 向下移, i++

AC 代碼

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        
        
        if (matrix==null || matrix.length==0) return false;
        
        int i=0, j=matrix[0].length-1;
        
        while(i=0){
            if (target