[LeetCode] Search a 2D Matrix [25]

题目

Write an efficient algorithm that searches for a value in an m x n matrix.
This matrix has the following properties:

  • Integers in each row are sorted from left to right.
  • The first integer of each row is greater than the last integer of the previous row.

For example,

Consider the following matrix:

[
  [1,   3,  5,  7],
  [10, 11, 16, 20],
  [23, 30, 34, 50]
]

Given target = 3, return true.

原题链接(点我)

解题思路

二维数组中的查找,这是个简单的题,根据题意可以推出,这个二维数组其实是一个有序的一维数组。解决思路也很容易想到,每次比较每一维最后一个元素,如果该元素比要找的元素小,说明这个行不可能含该元素;如果相等,那就找到了,如果最后一个元素比要找元素大,说明该元素如果出现比在这一行。然后再在这一行中就行查找(可以用顺序,也可二分)。

代码实现

class Solution {
public:
    bool searchMatrix(vector<vector<int> > &matrix, int target) {
        int m = matrix.size();
        if(m<=0) return false;
        int n = matrix[0].size();
        for(int i=0; i<m; ++i){
            if(matrix[i][n-1] == target)
                return true;
            else if(matrix[i][n-1] < target)
                continue;
            else{
                for(int j=0; j<n; ++j)
                    if(matrix[i][j] == target)
                        return true;
                return false;
            }
        }
        return false;
    }
};

如果你觉得本篇对你有收获,请帮顶。

另外,我开通了微信公众号--分享技术之美,我会不定期的分享一些我学习的东西.

你可以搜索公众号:swalge 或者扫描下方二维码关注我

(转载文章请注明出处: http://blog.csdn.net/swagle/article/details/29564491
)

[LeetCode] Search a 2D Matrix [25]

时间: 2024-10-24 01:18:20

[LeetCode] Search a 2D Matrix [25]的相关文章

leetcode——Search a 2D Matrix 二维有序数组查找(AC)

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous ro

[leetcode]Search a 2D Matrix @ Python

原题地址:https://oj.leetcode.com/problems/search-a-2d-matrix/ 题意: Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer o

LeetCode: Search a 2D Matrix [074]

[题目] Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previo

leetcode Search a 2D Matrix II

题目连接 https://leetcode.com/problems/search-a-2d-matrix-ii/ Search a 2D Matrix II Description Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted in ascend

LeetCode: Search a 2D Matrix 解题报告

Search a 2D Matrix Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer

[LeetCode] Search a 2D Matrix II 搜索一个二维矩阵之二

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted in ascending from left to right. Integers in each column are sorted in ascending from top to bottom.

LeetCode -- Search a 2D Matrix &amp; Search a 2D Matrix II

Question: Search a 2D Matrix Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the la

[Leetcode] search a 2d matrix 搜索二维矩阵

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous ro

LeetCode——Search a 2D Matrix

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted from left to right. The first integer of each row is greater than the last integer of the previous ro