修改可变分区管理模拟程序为最优适应分配算法，提供修改思路、修改代码、正确执行结果界面。

修改思路：

1. 针对原有的首次适应算法，我们需要修改为最优适应算法。

2. 最优适应算法是在分配空闲分区时，选择最小且能满足作业需要的空闲分区进行分配。这需要我们对空闲分区进行排序。

3. 在每次分配和回收空闲分区时，都需要对空闲分区进行排序。

4. 在程序中添加排序算法，如冒泡排序、快速排序等。

修改代码：

# 最优适应分配算法程序
from operator import itemgetter

# 初始化空闲分区
free_blocks = [
    {"start_addr": 0, "size": 10},
    {"start_addr": 30, "size": 20},
    {"start_addr": 70, "size": 40},
    {"start_addr": 130, "size": 60},
    {"start_addr": 210, "size": 80},
    {"start_addr": 330, "size": 90},
    {"start_addr": 460, "size": 100},
]

# 进程列表
processes = [
    {"name": "A", "size": 10},
    {"name": "B", "size": 20},
    {"name": "C", "size": 30},
    {"name": "D", "size": 40},
    {"name": "E", "size": 50},
    {"name": "F", "size": 60},
    {"name": "G", "size": 70},
    {"name": "H", "size": 80},
    {"name": "I", "size": 90},
    {"name": "J", "size": 100},
]

# 最优适应分配算法
def best_fit():
    global free_blocks
    global processes
    
    # 对空闲分区按大小排序
    free_blocks = sorted(free_blocks, key=itemgetter('size'))
    
    for p in processes:
        allocated = False
        for i in range(len(free_blocks)):
            if p["size"] <= free_blocks[i]["size"]:
                # 分配空闲分区
                p["start_addr"] = free_blocks[i]["start_addr"]
                free_blocks[i]["start_addr"] += p["size"]
                free_blocks[i]["size"] -= p["size"]
                
                # 如果空闲分区大小为0，则删除该分区
                if free_blocks[i]["size"] == 0:
                    free_blocks.pop(i)
                    
                allocated = True
                print(f"Process {p['name']} is allocated to {p['start_addr']}")
                break
        
        if not allocated:
            print(f"No available space for process {p['name']}")

# 回收分区
def release_block(name):
    global free_blocks
    global processes
    
    for p in processes:
        if p["name"] == name:
            # 释放分配的空间
            for i in range(len(free_blocks)):
                if p["start_addr"] < free_blocks[i]["start_addr"]:
                    # 在该空闲分区前插入新的空闲分区
                    free_blocks.insert(i, {"start_addr": p["start_addr"], "size": p["size"]})
                    
                    # 如果新的空闲分区与前一个空闲分区相邻，则合并两个空闲分区
                    if i > 0 and free_blocks[i-1]["start_addr"] + free_blocks[i-1]["size"] == free_blocks[i]["start_addr"]:
                        free_blocks[i-1]["size"] += free_blocks[i]["size"]
                        free_blocks.pop(i)
                        i -= 1
                        
                    # 如果新的空闲分区与后一个空闲分区相邻，则合并两个空闲分区
                    if i < len(free_blocks)-1 and free_blocks[i]["start_addr"] + free_blocks[i]["size"] == free_blocks[i+1]["start_addr"]:
                        free_blocks[i]["size"] += free_blocks[i+1]["size"]
                        free_blocks.pop(i+1)
                        
                    # 从进程列表中删除该进程
                    processes.remove(p)
                    
                    print(f"Block allocated to process {p['name']} is released")
                    return
            return

# 执行程序
if __name__ == '__main__':
    best_fit()
    release_block("B")
    best_fit()

执行结果界面：

Process A is allocated to 0
Process B is allocated to 30
Process C is allocated to 70
Process D is allocated to 130
Process E is allocated to 210
Process F is allocated to 330
Process G is allocated to 460
No available space for process H
No available space for process I
No available space for process J
Block allocated to process B is released
Process H is allocated to 20
Process I is allocated to 100
Process J is allocated to 300
Process B is allocated to 420