1. **Problem 1: Minimum Spanning Tree (MST) using Kruskal's Algorithm for Graph 1**
Given edges and weights, find MST by sorting edges ascending by weight and adding edges without forming cycles.
Edges sorted by weight: (B-C:1), (A-D:2), (C-F:3), (E-F:1), (H-I:2), (D-E:7), (B-E:5), (A-B:5), (E-H:3), (F-I:4), (G-H:8), (D-G:6), (B-F:8), (C-D:2), (A-C:4)
Step 1: Add (B-C) weight 1
Step 2: Add (E-F) weight 1
Step 3: Add (A-D) weight 2
Step 4: Add (H-I) weight 2
Step 5: Add (C-D) weight 2
Step 6: Add (E-H) weight 3
Step 7: Add (C-F) weight 3
Step 8: Add (F-I) weight 4
Step 9: Add (A-B) weight 5
Stop adding edges when all vertices connected.
Total MST weight = $1+1+2+2+2+3+3+4+5=23$
2. **Problem 2: MST using Kruskal's Algorithm for Graph 2**
Edges sorted ascending:
(F-G:5), (G-D:6), (A-B:6), (D-E:6), (A-G:7), (C-D:7), (B-C:8), (E-F:8), (B-F:8), (B-D:9), (F-D:9)
Step 1: Add (F-G) weight 5
Step 2: Add (G-D) weight 6
Step 3: Add (A-B) weight 6
Step 4: Add (D-E) weight 6
Step 5: Add (A-G) weight 7
Step 6: Add (C-D) weight 7
Adding any other edge forms cycle.
Total MST weight = $5+6+6+6+7+7=37$
3. **Problem 3: MST for Graph 3**
Edges sorted ascending:
(E-F:1), (B-C:4), (H-I:2), (A-D:2), (C-F:3), (E-H:3), (F-I:4), (A-B:5), (B-E:5), (D-G:6), (D-E:7), (G-H:8)
Step 1: Add (E-F) weight 1
Step 2: Add (H-I) weight 2
Step 3: Add (A-D) weight 2
Step 4: Add (C-F) weight 3
Step 5: Add (E-H) weight 3
Step 6: Add (F-I) weight 4
Step 7: Add (B-C) weight 4
Step 8: Add (A-B) weight 5
Step 9: Add (B-E) weight 5
Stop when all vertices connected.
Total MST weight = $1+2+2+3+3+4+4+5+5=29$
4. **Problem 4: MST using Prim's Algorithm for Graph 4**
Start from vertex 1.
Step 1: Choose edge (1-6) weight 20 (minimum adjacent to 1)
Step 2: Choose edge (6-2) weight 25 (minimum adjacent to 1 or 6)
Step 3: Choose edge (2-5) weight 15 (minimum adjacent to 1,6,2)
Step 4: Choose edge (5-4) weight 30 (minimum adjacent to 1,6,2,5)
Step 5: Choose edge (4-3) weight 10 (minimum adjacent to 1,6,2,5,4)
Total MST weight = $20+25+15+30+10=100$
**Summary:**
- Problem 1 MST weight: 23
- Problem 2 MST weight: 37
- Problem 3 MST weight: 29
- Problem 4 MST weight: 100
Each MST constructed step-by-step as above.
Mst Kruskal Prim 63C283
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