In Walter Washington's campaign headquarters, the stacks of roast beef and rye disappeared as two dozen workers cheered their man on television.

At Marion Barry's office, they yelled happily when a Southeast bookie called in to report the street odds changing for their candidate.

At Sterling Tucker's office, the sharp zip of the scissors and the paper cutter could be heard as workers tore up red, black and white construction paper for victory confetti.

The last 100 hours of a long, grueling campaign for the three Democratic contenders for mayor of the District of Columbia had started. Motorcades were dispatched. Frantic calls made to the printer for the latest flyer with the latest endorsement.

All the systems for the "Get Out the Vote" operations for primary day today had to be finely tuned. A dozen volunteer voices echoed: "Do you have a ride to the polls?"

On Saturday morning - marked "Go Day" on a yellow slip of paper in Walter Washington's campaign offices - eight staff members enjoyed a leisurely breakfast of ham, eggs, home fries, grits and biscuits from the Florida Avenue Grill. Thus energized, their pace didn't stop until a Sunday night rally for poll workers.

Towering over the command center in a maze of offices in a downtown bank building - was R. Calvin Lockridge.

Lockridge, school board member from Ward 8, has divided the he work load in the final hours of strategy with field operations director Warren Graves. Both veterans of political campaigns, they appeared absolutely calm, though they both characterized to last weekend as the one that "really gets the adrenalin going."

"Right now we are peaking, we are gaining every day," said Lockridge Sunday afternoon before the rally. The strategy is done, now it's a question of how do you pull the subsystems together." Four years ago Lockridge, 44, coordinated War 8 for Clifford Alexander's campaign for mayor, the only ward the candidate swept. Lockridge's better-than-6-foot frame moved quickly across the room, stopping briefly to confer with Rick Lyons, 25, a composer, who was feeding all of Washington's statements to the radio stations, and William J. Tatum, a former Presbyterian minister, who was overseeing the phone bank.

He was asked to recall the hardest moment since he formally joined the campaign in July. "Admitting we were behind and deciding to admit it openly," he said slowly. "It was one of those sessions that lasted until 5 a.m. Then we decided, let's see all the elements and see what we can control." Mistakes are never dwelt upon, until the game is over. He checked the poll workers instruction, including the advisory, "pick up any sample ballots thrown to the ground."

"I love the whole art of strategy. Campaigning is a war, with the long hours, the exhaustion only picking you up." The last 100 hours did appear to be a body count, as Lockridge went over the names of poll workers. "The most important step is to have an alternative in case the communications system breaks down."

Anita Bonds, Marion Barry's deputy campaign manager, had lived this last phase of a campaign before. She knew, as did most of the women in all three offices, that you wear flat sandals, that you sit down and eat with the children before coming into the office, that the last weekend might never end.

Bonds, 33, arrived at the downtown three-story storefront at noon Saturday. She didn't leave until 9:15 Sunday morning. "I become more enthusiastic as we get to D-Day. It does take a while for things to gel," said Bonds, as she gingerly stepped over a stack of envelopes from the precinct workers. She picked up the phone to call her ward coordinators but stopped instead to send a crew off to the post office with the final mailing for the undecideds and to console a worker whose arms were bruised from the double-decker campaign bus. And she smiled at a conversation among the phone workers. "Oh, yes, what he has been doing is so typical." "He's was, of course, another candidate.

Over the weekend the Barry office had a peaceful hum. "We are rolling," said Bonds. "The last weekend we put most of the volunteers out in the street, working door-to-door. Right now I'm making sure the material flows from this office." Bonds was a nonpolitical housewife in Southeast when D.C. delegate Walter Fauntroy asked her to help with Barry's school board race seven years ago. Since then she has worked for the campaigns of Jimmy Carter, Clifford Alexander and Walter Fauntroy. "The beauty of this is organizing people. When you make that initial eye contact and someone understands, that's encouraging."

When Barry returned from a fund-raiser at midnight on Satureday night, Bonds was on her hands and knees tacking posters to stakes. At 4 p.m. the next afternoon, she returned, her eyes showing the long hours but her smile intact. She started on another list. The top item - a Thermos for the first crew at the polls.

Nothing is very orderly in a campaign, offered Lee Carty, Sterling Tucker's deputy campaign manager. Nothing is typical.

"But the variety is good. And nothing has been more satisfying than watching people get interested, watching people realize that elections do matter," said Carty, an editor and publicist who has been laboring for Tucker the past year.

By her desk in the converted drug store headquarters was a large floor fan that droned on and on. On Saturday afternoon, headquarters was almost abandoned, explained Carty, "because our efforts have been decentralized into the ward offices. We have finished the tag ends of the mailing and the phone bank is operating out of the ward offices and private homes."

Over the weekend the Tucker staff sent out over 20,000 pieces of first-class mail, including a Tuckergram, that urged, "September 12 can be the day we vote the tired blood out of the District Building."

Only one phase of the campaign gave her the jitters. "Vacation time, when people were away during the first part of August. That was awful, slow. We needed fresh people and they weren't there. We needed some momentum but nothing grows in August.

"But now," she said, "the momentum is driving everyone. Everything is ready, everything is in place. What can I say."

Not everyone in the campaign offices has the political veteran's blend of nonchalance and fierce competition. For them, the afternoons of counting posters, labeling envelopes and dialing the undecideds were their first look at the political process.

Johnnie Smith, 20, a second-year accounting student at the University of the District of Columbia, said his two weeks on the Washington campaign phone bank have been intriguing. "I wanted to talk to people and find out what is politics. And the spirit is the people," said Smith. "But my own political sense about the importance of these offices, as well as the importance of political opinions has changed."

Rosalyce Simms had planned to spend this summer as a camp director. Instead she has managed Barry's telephone bank, staffed by eight regular volunteers and additional students.

"What I have learned is that you really can live in the city, but you don't understand it, until you start talking to people and you have to take a stand," said Simms, a 32-year-old teacher.

The volunteer coordinator of Tucker's campaign, Alicia Blassengale, 33, has weathered the guilt feelings she suffered at having to leave her two children and husband for long hours and the panic of not having volunteers and handiwork there at the same time.

"I thought it would be exciting to use all my talents, organization, leadership, handicrafts," said Blassengale. "But the lesson has been is that there are not only political types, that the political people aren't all the same but that all the diversity of the city can be reached."