LeetCode-in-All

74. Search a 2D Matrix

Medium

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.

Example 1:

Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3

Output: true

Example 2:

Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13

Output: false

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 100
• -104 <= matrix[i][j], target <= 104

Solution

#include <vector>

class Solution {
public:
    bool searchMatrix(const std::vector<std::vector<int>>& matrix, int target) {
        int endRow = matrix.size();
        int endCol = matrix[0].size();
        int targetRow = 0;
        bool result = false;

        for (int i = 0; i < endRow; i++) {
            if (matrix[i][endCol - 1] >= target) {
                targetRow = i;
                break;
            }
        }

        for (int i = 0; i < endCol; i++) {
            if (matrix[targetRow][i] == target) {
                result = true;
                break;
            }
        }

        return result;
    }
};

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