【leetcode】74. Search a 2D Matrix & 240. Search a 2D Matrix II

题目如下:这两个题目可以用同样的代码来解答,因此就合并在一起了。

题目一:

题目二:

解题思路:两个题目的唯一区别在于第二个题目下一行的最小值不一定会小于前一行的最大值。但是不管怎么样我们可以确定的是,如果某一行的最小值都比target要大,那么这一行之后的值都比target要大。如果target介于某一行的最小值和最大值之间,那么target有可能在这一行。至于如何判断target是否存在,因为数组有序,用二分查找即可。

代码如下:

class Solution(object):
    def searchMatrix(self, matrix, target):
        import  bisect
        ROW = len(matrix)
        if ROW == 0:
            return False
        COLUMN = len(matrix[0])
        if COLUMN == 0:
            return False
        for i in matrix:
            if i[0] <= target and i[-1] >= target:
                inx = bisect.bisect_left(i,target)
                if i[inx] == target:
                    return True
            elif i[0] > target:
                break
        return False

原文地址:https://www.cnblogs.com/seyjs/p/8890874.html

时间: 2024-08-04 01:11:23

【leetcode】74. Search a 2D Matrix & 240. Search a 2D Matrix II的相关文章

【LeetCode】109&amp; - Convert Sorted List to Binary Search Tree&amp;Convert Sorted Array to Binary Search Tree

Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. Solution 1:  recursion runtime: 28ms. /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(i

【Leetcode】109. Convert Sorted List to Binary Search Tree

Question: Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node n

【leetcode】108. Convert Sorted Array to Binary Search Tree

题目如下: Given an array where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by m

【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

【LeetCode】Word Search II 解题报告

[题目] Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The sa

【LeetCode】Spiral Matrix II

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]此题与Spiral Matrix类似,可以用相同的方法解决,相比之下,此题比前一题简单 publ

【LeetCode】Validate Binary Search Tree

Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys

【LeetCode】Search Insert Position (2 solutions)

Search Insert Position Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume no duplicates in the array. Here are few examples.[1,3,5,

【一天一道LeetCode】#109. Convert Sorted List to Binary Search Tree

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. (二)解题 本题大意:给定一个单向链表,构造出平衡二叉搜索树 解题思路:参考[一天一道Leet