74. Search a 2D Matrix刷题笔记

题目描述 用了两个二分查找法。当然也可以把matrix转为数组来索引

class Solution:
    def searchMatrix(self, matrix: List[List[int]], target: int) -> bool:
        low = 0
        high = len(matrix)-1
        mid = 0
        while low<=high:
            mid = (high+low)//2
            if target < matrix[mid][0]:
                high = mid-1
            elif target>matrix[mid][-1]:
                low = mid+1
            else:
                break
        i = mid
        low = 0
        high = len(matrix[0])-1
        while low<=high:
            mid = (low+high)//2
            if target==matrix[i][mid]:
                return True
            if target<matrix[i][mid]:
                high = mid-1
            else:
                low = mid+1
        return False

运行结果：