选择排序

//测试调用
    NSMutableArray *arr = [@[@"3", @"5", @"4", @"2", @"6"] mutableCopy];
    arr = [self selectSortWithArray:arr];
    NSLog(@"result = %@", arr);

/**
 * 方法名：selectSort 说明：选择排序O(N^2)的算法
 */
- (NSMutableArray *)selectSortWithArray:(NSMutableArray *)array {
    for (int i = 0; i < array.count; i++) {
        NSInteger j = [self selectSortWithArray:array index:i];
        if (i != j) {
            NSString *temp = array[j];
            array[j] = array[i];
            array[i] = temp;
        }
    }
    return array;
}

- (NSInteger)selectSortWithArray:(NSMutableArray *)array index:(NSInteger)index {
    NSString *min = array[index];
    NSInteger minPos = index;
    for (int i = (int)index + 1; i < array.count; i++) {
        if ([array[i] compare:min] == NSOrderedAscending) {
            min = array[i];
            minPos = i;
        }
    }
    return minPos;
}