Search a 2D Matrix II

Desicription

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 in ascending from left to right.
  • Integers in each column are sorted in ascending from top to bottom.

Example:

Consider the following matrix:

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[
[1, 4, 7, 11, 15],
[2, 5, 8, 12, 19],
[3, 6, 9, 16, 22],
[10, 13, 14, 17, 24],
[18, 21, 23, 26, 30]
]

Given target = 5, return true.

Given target = 20, return false.

Solution

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class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int row = matrix.size();
if(row == 0) {
return false;
}
int col = matrix[0].size();
if(col == 0) {
return false;
}
int currentRow = 0;
int currentCol = col - 1;
while(true) {
if(currentRow >= row || currentCol < 0) {
return false;
}
auto current = matrix[currentRow][currentCol];
if(target == current) {
return true;
}
else if(target < current) {
currentCol--;
}
else if(target > current) {
currentRow++;
}
}
return false;
}
};