0074-search-a-2d-matrix.cs

public class Solution {
    public bool SearchMatrix(int[][] matrix, int target) {
        int ROWS = matrix.Length;
        int COLS = matrix[0].Length;
        int top = 0, bot = ROWS - 1;
        int row = 0;

        while(top <= bot) {
            row = (top + bot) / 2;
            if(target > matrix[row][COLS-1]) top = row + 1;
            else if (target < matrix[row][0]) bot = row - 1;
            else break;
        }

        if (top > bot) return false;

        int l = 0, r = COLS - 1;

        while (l <= r) {
            int m = (l + r) / 2;
            if (target > matrix[row][m]) l = m + 1;
            else if (target < matrix[row][m]) r = m - 1;
            else return true;
        }

        return false;
    }
}