// Approach 1: Check the first and last digit in each row to see if the target is inside it. If so, search the row for the target.
/**
 * @param {number[][]} matrix
 * @param {number} target
 * @return {boolean}
 */
var searchMatrix = function(matrix, target) {
    var result = false;
    var height = matrix.length;

    // Check the first digit in each row.
    for (var row=0; row<height; row++) {
        var width = matrix[row].length;
        var first = matrix[row][0];
        var last = matrix[row][width - 1];

        if (target === first || target === last) {
            // Found target.
            result = true;
            break;
        }
        else if (target > first && target < last) {
            // Check this row for target.
            for (var i=1; i<width - 1; i++) {
                if (target === matrix[row][i]) {
                    result = true;
                    break;
                }
            }
        }
    }

    return result;
};