Search a 2D Matrix

最新推荐文章于 2022-08-05 12:18:43 发布

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本文介绍了一种高效的算法用于在m x n矩阵中搜索指定值。矩阵特性为每行从左到右排序，且每行最后一个数大于上一行的第一个数。通过双指针策略从矩阵右上角开始搜索，实现快速定位目标值。

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.

bool searchMatrix(vector<vector<int> > &matrix, int target)
{
    int i = 0, j = matrix[0].size() - 1;

    while (i < matrix.size() && j >= 0)
    {
        if (target == matrix[i][j])
            return true;
        else if (target < matrix[i][j])
            j--;
        else
            i++;
    }

    return false;
}