内存泄漏for循环

Question

我尝试用Instruments分析我的代码，我看到NSString * key中的内存泄漏：

for (int i=1; i<=10; i++) {
    for (int j=1; j<=10; j++) {           
        NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
        NSString *key=[[[[NSNumber numberWithInt:i] stringValue] stringByAppendingString:@"-"] stringByAppendingString:[[NSNumber numberWithInt:j] stringValue]];
        NSString *myChar=[NSString stringWithString:[tmpArray objectAtIndex:index]]; 
        [myDict setValue:myChar forKey:key];                     
        index +=1;
        [pool drain];            
    }
}

有人有想法吗？感谢。