Return all top-scoring solver configurations and display as tabs

main.go

@@ -1152,7 +1152,7 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 
 		if len(studentIDs) == 0 {
 			w.Header().Set("Content-Type", "application/json")
-			json.NewEncoder(w).Encode(map[string]any{"rooms": []any{}, "score": 0})
+			json.NewEncoder(w).Encode(map[string]any{"solutions": []any{}})
 			return
 		}
 
@@ -1360,9 +1360,47 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 		initialAssignment := make([]int, n)
 		copy(initialAssignment, assignment)
 
-		bestAssignment := make([]int, n)
-		copy(bestAssignment, assignment)
 		bestScore := score(assignment)
+		var bestSolutions [][]int
+		seen := map[string]bool{}
+		normalizeKey := func(a []int) string {
+			rm := map[int][]int{}
+			for i, room := range a {
+				rm[room] = append(rm[room], i)
+			}
+			var gs [][]int
+			for _, members := range rm {
+				slices.Sort(members)
+				gs = append(gs, members)
+			}
+			slices.SortFunc(gs, func(a, b []int) int { return a[0] - b[0] })
+			var buf strings.Builder
+			for _, g := range gs {
+				for i, m := range g {
+					if i > 0 {
+						buf.WriteByte(',')
+					}
+					buf.WriteString(strconv.Itoa(m))
+				}
+				buf.WriteByte(';')
+			}
+			return buf.String()
+		}
+		addSolution := func(a []int, s int) {
+			if s > bestScore {
+				bestScore = s
+				bestSolutions = nil
+				seen = map[string]bool{}
+			}
+			if s == bestScore {
+				key := normalizeKey(a)
+				if !seen[key] {
+					seen[key] = true
+					bestSolutions = append(bestSolutions, slices.Clone(a))
+				}
+			}
+		}
+		addSolution(assignment, bestScore)
 
 		roomCount := func(a []int, room int) int {
 			c := 0
@@ -1498,37 +1536,32 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 		}
 
 		copy(assignment, initialAssignment)
-		s := hillClimb(assignment)
+		addSolution(assignment, hillClimb(assignment))
-		if s > bestScore {
-			bestScore = s
-			copy(bestAssignment, assignment)
-		}
 
 		for range 30 {
 			if randomPlacement() {
-				s := hillClimb(assignment)
+				addSolution(assignment, hillClimb(assignment))
-				if s > bestScore {
-					bestScore = s
-					copy(bestAssignment, assignment)
-				}
 			}
 		}
 
 		for range 200 {
-			perturb(bestAssignment, 2+rand.Intn(3))
+			src := bestSolutions[rand.Intn(len(bestSolutions))]
-			s := hillClimb(assignment)
+			perturb(src, 2+rand.Intn(3))
-			if s > bestScore {
+			addSolution(assignment, hillClimb(assignment))
-				bestScore = s
-				copy(bestAssignment, assignment)
-			}
 		}
 
 		type roomMember struct {
 			ID   int64  `json:"id"`
 			Name string `json:"name"`
 		}
+		type solutionResult struct {
+			Rooms [][]roomMember `json:"rooms"`
+			Score int            `json:"score"`
+		}
+		var results []solutionResult
+		for _, sol := range bestSolutions {
 			roomMap := map[int][]roomMember{}
-		for i, room := range bestAssignment {
+			for i, room := range sol {
 				sid := studentIDs[i]
 				roomMap[room] = append(roomMap[room], roomMember{ID: sid, Name: studentName[sid]})
 			}
@@ -1540,8 +1573,20 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 				}
 			}
 			slices.SortFunc(rooms, func(a, b []roomMember) int { return strings.Compare(a[0].Name, b[0].Name) })
+			results = append(results, solutionResult{Rooms: rooms, Score: bestScore})
+		}
+		slices.SortFunc(results, func(a, b solutionResult) int {
+			for i := range min(len(a.Rooms), len(b.Rooms)) {
+				for j := range min(len(a.Rooms[i]), len(b.Rooms[i])) {
+					if c := strings.Compare(a.Rooms[i][j].Name, b.Rooms[i][j].Name); c != 0 {
+						return c
+					}
+				}
+			}
+			return 0
+		})
 
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]any{"rooms": rooms, "score": bestScore})
+		json.NewEncoder(w).Encode(map[string]any{"solutions": results})
 	}
 }

static/trip.js

@@ -422,7 +422,9 @@ document.getElementById('solve-btn').addEventListener('click', async () => {
         const result = await api('POST', '/api/trips/' + tripID + '/solve');
         const container = document.getElementById('solver-results');
         container.innerHTML = '';
-        for (let i = 0; i < result.rooms.length; i++) {
+
+        const renderSolution = (sol, parent) => {
+            for (let i = 0; i < sol.rooms.length; i++) {
                 const card = document.createElement('wa-card');
                 card.className = 'room-card';
                 const label = document.createElement('div');
@@ -431,10 +433,10 @@ document.getElementById('solve-btn').addEventListener('click', async () => {
                 card.appendChild(label);
                 const tags = document.createElement('div');
                 tags.className = 'tags';
-            const roomIDs = result.rooms[i].map(m => m.id);
+                const roomIDs = sol.rooms[i].map(m => m.id);
                 const violations = [];
-            for (const a of result.rooms[i]) {
+                for (const a of sol.rooms[i]) {
-                for (const b of result.rooms[i]) {
+                    for (const b of sol.rooms[i]) {
                         if (a.id === b.id) continue;
                         const eff = lastOveralls[a.id]?.[b.id];
                         if (eff && eff.kind === 'prefer_not') {
@@ -442,7 +444,7 @@ document.getElementById('solve-btn').addEventListener('click', async () => {
                         }
                     }
                 }
-            for (const member of result.rooms[i]) {
+                for (const member of sol.rooms[i]) {
                     const tag = document.createElement('wa-tag');
                     tag.size = 'small';
                     tag.style.cursor = 'pointer';
@@ -453,11 +455,11 @@ document.getElementById('solve-btn').addEventListener('click', async () => {
                     else if (hasPrefers && !gotPrefer) tag.variant = 'warning';
                     tag.textContent = member.name;
                     tag.addEventListener('click', () => {
-                    const card = document.querySelector('[data-student-id="' + member.id + '"]');
+                        const studentCard = document.querySelector('[data-student-id="' + member.id + '"]');
-                    if (!card) return;
+                        if (!studentCard) return;
-                    const cDet = [...card.querySelectorAll('wa-details')].find(d => d.summary === 'Constraints');
+                        const cDet = [...studentCard.querySelectorAll('wa-details')].find(d => d.summary === 'Constraints');
                         if (cDet) cDet.open = true;
-                    card.scrollIntoView({ behavior: 'smooth', block: 'center' });
+                        studentCard.scrollIntoView({ behavior: 'smooth', block: 'center' });
                     });
                     tags.appendChild(tag);
                 }
@@ -471,11 +473,33 @@ document.getElementById('solve-btn').addEventListener('click', async () => {
                 } else {
                     card.appendChild(tags);
                 }
-            container.appendChild(card);
+                parent.appendChild(card);
+            }
+        };
+
+        const solutions = result.solutions;
+        if (solutions.length === 1) {
+            renderSolution(solutions[0], container);
+        } else if (solutions.length > 1) {
+            const tabGroup = document.createElement('wa-tab-group');
+            for (let si = 0; si < solutions.length; si++) {
+                const tab = document.createElement('wa-tab');
+                tab.slot = 'nav';
+                tab.panel = 'sol-' + si;
+                tab.textContent = 'Option ' + (si + 1);
+                tabGroup.appendChild(tab);
+            }
+            for (let si = 0; si < solutions.length; si++) {
+                const panel = document.createElement('wa-tab-panel');
+                panel.name = 'sol-' + si;
+                renderSolution(solutions[si], panel);
+                tabGroup.appendChild(panel);
+            }
+            container.appendChild(tabGroup);
         }
         const scoreDiv = document.createElement('div');
         scoreDiv.className = 'solver-score';
-        scoreDiv.textContent = 'Score: ' + result.score;
+        scoreDiv.textContent = 'Score: ' + (solutions[0]?.score ?? 0) + (solutions.length > 1 ? ' (' + solutions.length + ' options)' : '');
         container.appendChild(scoreDiv);
     } catch (e) {
         const container = document.getElementById('solver-results');