LeeCode算法一

OC版本：

-(NSMutableArray*)hashMapTest{

    int target = 6;

    NSArray * array = [NSArray arrayWithObjects:@"2",@"3",@"5",@"9",@"1",nil];
    if (array == NULL || array.count < 2) {
        return [NSMutableArray arrayWithCapacity:0];
    }
    NSMutableArray * arr = [NSMutableArray array];
    NSMutableDictionary * dict = [NSMutableDictionary dictionary];
    for (int i = 0; i < array.count ; i++) {
        if ([dict objectForKey:[NSString stringWithFormat:@"%d",target - [array[i] intValue]]]) {
            NSString * index = [dict valueForKey:[NSString stringWithFormat:@"%d",target - [array[i] intValue]]];
            [arr addObject:index];
            [arr addObject:[NSString stringWithFormat:@"%d",i]];
            NSLog(@"index = %@ & i = %d",index,i);
            NSLog(@"arr%@",arr);
            return arr;
        }
        [dict setValue:[NSString stringWithFormat:@"%d",i] forKey:array[i]];
    }
    NSLog(@"arr%@",arr);
    return arr;
}

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