【剑指Offer】4. 二维数组中的查找

Consider the following matrix:
[
  [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]
]

Given target = 5, return true.
Given target = 20, return false.

public class Solution {
    public boolean Find(int target, int [][] array) {
        int rows = array.length;
        int cols = array[0].length;
        int r = 0, c = cols - 1; // 右上到左下缩小范围
        while(r <= rows-1 && c >= 0) {
            if(target == array[r][c])
                return true;
            else if(target > array[r][c])
                r++;
            else
                c--;
        }
        return false;
    }
}