LeetCode Search a 2D Matrix

最新推荐文章于 2024-01-11 10:31:20 发布

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最新推荐文章于 2024-01-11 10:31:20 发布

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本文介绍了一种高效的算法，用于在一特殊格式的二维矩阵中查找特定数值。该矩阵每一行的整数从左到右递增排序，并且每行的第一个整数大于前一行的最后一个整数。文章提供了具体的矩阵示例及C++实现代码。

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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 row.

For example,

Consider the following matrix:

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

Given target = 3, return true.

Tips:

Notice user defined compare function's parameter order.

Solution:

class Solution {
public:
    class Comp{
        public:
            bool operator()(const int& target,const vector<int> &array){
                return target<array[0];
            }
    };
    bool searchMatrix(vector<vector<int> > &matrix, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> >::iterator iter=upper_bound(matrix.begin(),matrix.end(),target,Comp());
        if(iter==matrix.begin())
            return false;
        --iter;
        return binary_search((*iter).begin(),(*iter).end(),target);        
    }
};